Basis Data Terdistribusi

<a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><br /> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Teknologi database cenderung membentuk suatu konfigurasi sistem pengolahan data yang terpusat.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Secara teor<span lang="IN">e</span>tis datab<span lang="IN">a</span>se dapat didistribusikan dimana datanya didistribusikan ke berbagai tipe konfigurasi </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Sebelum mendistribusikan database perlu ditentukan lokasi dan mapping antara database akan ditanam<span lang="IN">k</span>an atau dilaksanakan.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jadi data dapat berada dilokasi yang jauh, lalu sistem yang mencarinya. </div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b>Konsep Basis Data Terdistribusi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->1.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]-->Sistem Komputasi Terdistribusi adalah </div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo2; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->sejumlah elemen proses yang terkoneksi melalui jaringan komputer dan saling bekerjasama dalam melakukan suatu tugas </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->2.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]-->Basis Data Terdistribusi adalah </div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo2; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->kumpulan basis-basis data yang saling berhubungan secara logika dan tersebar pada sebuah jaringan komputer </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->3.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]-->Sistem Manajemen Basis Data adalah </div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo2; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->sebuah sistem software yang mengelola basis data terdistribusi </div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b><span lang="IN">Distributed Processing (Distributed Computing)</span></b></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->1.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Apa itu Distributed Processing (Distributed Computing)?</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->2.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Beberapa sinonim dari Distributed Processing:</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Distributed Function: Distribusi fungsi (CPU atau I/O) meskipun dalam sistem single-processor komputer.</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Distributed Computing System: Interkoneksi sejumlah elemen-elemen pengolahan (computing device yang dapat mengeksekusi program di masing-masing) dalam suatu jaringan komputer dan bekerjasama dalam menjalankan suatu tugas.</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Network</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Multiprocessors</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Timeshared systems</span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->3.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Apa yang didistribusikan?</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Processing logic, seperti definisi dari Distributed Computing System diatas.</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Functions, pendelegasian ke bermacam-macam hardware/software (tergantung fungsi komputer)</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Data, pendistribusian data ke sejumlah site pengolahan.</span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Control, kontrol eksekusi sejumlah task secara terdistribusi.</span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <b>DEFINISI<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b>Basis Data Terdistribusi </b>adalah kumpulan data logic yang saling berhubungan secara fisik terdistribusi dalam jaringan komputer,  yang tidak tergantung dari program aplikasi sekarang maupun masa yang akan datang.</div> <div class="MsoNoSpacing"> File merupakan kumpulan data yang dirancang untuk suatu aplikasi atau sekumpulan aplikasi yang dekat hubungannya.</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 54.0pt; mso-list: l3 level1 lfo4; text-indent: -18.0pt;"> <!--[if !supportLists]-->1.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Distribusi data yang terpisah secara fisik akan menimbulkan masalah yang tidak dijumpai ketika database ada di komputer yang sama. </span></div> <div class="MsoNoSpacing">                 <span lang="IN" style="font-family: Wingdings; mso-ansi-language: IN; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Wingdings;">à</span><span lang="IN"> Inilah yang membedakan antara DDBS dengan Multiprocessor.</span></div> <div class="MsoNoSpacing" style="margin-left: 54.0pt; mso-list: l3 level1 lfo4; text-indent: -18.0pt;"> <!--[if !supportLists]-->2.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">DDBS bukan merupakan sistem dimana meskipun ada jaringan komputer, tapi databasenya hanya terletak disatu node dari jaringan tsb.</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 54.0pt;"> <br /></div> <div class="MsoNoSpacing"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgA1v0B0u6BOCxEkg-bItVX-QPawOpS_owLDIQD93dM9eONNBt0LmnYKCCedrAq3mZGwKHJ9B6B4XbtDCq5noAZYV317dZbIMgoejwf9jp0hgJwYwtGMlQQr9PuNbp7WYXxr6B9UNubnCM/s1600/basis+data.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="146" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgA1v0B0u6BOCxEkg-bItVX-QPawOpS_owLDIQD93dM9eONNBt0LmnYKCCedrAq3mZGwKHJ9B6B4XbtDCq5noAZYV317dZbIMgoejwf9jp0hgJwYwtGMlQQr9PuNbp7WYXxr6B9UNubnCM/s1600/basis+data.png" width="320" /></a></div> <br /> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> <b><u><span lang="IN">Jaringan Komputer atau Kolesi File, tidak cukup untuk membentuk DDBS</span>!!!</u></b><b><u><span lang="IN">.</span><span lang="IN"> </span><o:p></o:p></u></b></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> <b><u><span lang="IN"><br /></span></u></b></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1i80zgSmf73_8yypaPylmiYY9tVTezibLFTvDWgV_x7tvwOv7HH1PCPp0J_xN8uGuM7Ah2JUxWelkJEnWChe_exf7bg0oMM17jy4QufHzlQ7DYm6fC_YKs5TdcjWUs2cJckGmhMBg2fU/s1600/basis+2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="175" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1i80zgSmf73_8yypaPylmiYY9tVTezibLFTvDWgV_x7tvwOv7HH1PCPp0J_xN8uGuM7Ah2JUxWelkJEnWChe_exf7bg0oMM17jy4QufHzlQ7DYm6fC_YKs5TdcjWUs2cJckGmhMBg2fU/s1600/basis+2.png" width="320" /></a></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> <b><u><span lang="IN"><br /></span></u></b></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> <br /></div> <div class="MsoNoSpacing"> <br /> <div class="MsoNoSpacing"> <b>Contoh Basis Data Terdistribusi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l8 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Misalnya sebuah bank yang memiliki banyak cabang, bahkan di sebuah kota bisa terdiri dari beberapa cabang/kantor.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l8 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Masing-masing lokasi memiliki jaringan lokal sendiri, dan semua jaringan lokal itu dihubungkan satu sama lain membentuk sebuah jaringan nasional.</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b>Struktur Basis Data Terdistribusi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l5 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->1.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]-->Sebuah sistem basis data terdistribusi hanya mungkin dibangun dalam sebuah sistem jaringan komputer.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l5 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->2.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]-->Topologi Jaringan </div> <div class="MsoNoSpacing">                 a. Topologi <span lang="IN">B</span>intang (star)</div> <div class="MsoNoSpacing">                 b. Topologi Cincin (<span lang="IN">r</span>ing)</div> <div class="MsoNoSpacing">                 c. Topologi Bus</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l5 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->3.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]-->Perbedaan utama di antara berbagai topologi di atas terletak pada:</div> <div class="MsoNoSpacing">                 a. Biaya Instalasi </div> <div class="MsoNoSpacing">                 Biaya dalam membangun hubungan  link antar simpul.</div> <div class="MsoNoSpacing">                 b. Biaya Komunikasi </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> Waktu dan biaya dalam pengoperasian sistem berupa pengiriman data dari satu simpul ke simpula lain</div> <div class="MsoNoSpacing" style="text-indent: 36.0pt;"> c. Kehandalan </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> Frekuensi/tingkat kegagalan komunikasi yang terjadi.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> d. Ketersediaan </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> Tingkat kesiapan data yang dapat diakses sebagai antisipasi kegagalan komunikasi.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> <br /></div> <div class="MsoNoSpacing"> <b>Jenis Transaksi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l6 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Transaksi Lokal </div> <div class="MsoNoSpacing">                 Transaksi yang mengakses data pada suatu simpul (mesin/server) yang sama dengan simpul dari mana transaksi tersebut dijalankan.</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l4 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Transaksi Global.</div> <div class="MsoNoSpacing">                 Transaksi yang membutuhkan pengaksesan data di simpul yang berbeda dengan simpul dimana transaksi tersebut dijalankan, atau transaksi dari sebuah simpul yang membutuhkan pengaksesan data ke sejumlah simpul lainnya</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b>Ciri Ciri Basis Data Terdistribusi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l3 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Data disimpan di sejumlah tempat </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l3 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Prosessor pada tempat yang berbeda tersebut dihubungkan dengan jaringan komputer </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l3 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Sistem basis data terdistribusi bukan terdiri dari sekumpulan file yang berada pada berbagai tempat tetapi pada sebuah basis data di berbagai tempat </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l3 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Setiap tempat secara mandiri memproses permintaan user yang membutuhkan akses ke data di tempat tersebut dan juga mampu untuk memproses data yang tersimpan di tempat lain.</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b><span lang="IN">Teknologi DDBS (Distributed Database System)</span></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->1.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">merupakan gabungan dari dua pendekatan pengolahan data yang sama sekali berlawanan</span> :</div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo6; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--> <span lang="IN">Database System</span>,<span lang="IN"> dan </span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo6; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Teknologi Jaringan Komputer.</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->2.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Tujuan utama Database System</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo6; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Mengintegrasikan data dan sentralisasi, sehingga akses (deskripsi, manipulasi dan kontrol) terhadap data sangat terkontrol </span></div> <div class="MsoNoSpacing">                 <span lang="IN" style="font-family: Wingdings; mso-ansi-language: IN; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Wingdings;">à</span><span lang="IN"> <b>Integration, not Centralization</b></span><b><span lang="IN"> </span></b></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->3.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Tujuan utama Jaringan Komputer</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l1 level2 lfo6; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--> <span lang="IN">Membuat mode kerja yang benar-benar menghindari terjadinya sentralisasi beban kerja.</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->4.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><span lang="IN">Teknologi DDBS mengintegrasikan sistem database yang </span>terdistribusi<span lang="IN">, untuk menghasilkan suatu teknologi yang powerful dan menjanjikan </span></div> <div class="MsoNoSpacing">                 <span lang="IN" style="font-family: Wingdings; mso-ansi-language: IN; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Wingdings;">à</span><span lang="IN"> <u>Integration without Centralization</u></span><u><span lang="IN"> </span></u></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b>Keuntungan yang diberikan oleh sistem basis data terdistribusi</b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Pembagian dan pemakaian data dan kontrol yang tersebar</span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Pengelolaan secara transparan data yang terdistribusi </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Mengacu pada struktur organisasi </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Meningkatkan untuk berbagi dan otonomi lokal </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Meningkatkan ketersediaan data</div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Meningkatkan kehandalan </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Meningkatkan performasi kerja </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Memudahkan pengembangan sistem </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l7 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Kecepa</span>t<span lang="IN">an <i>query</i></span><i><span lang="IN"> </span></i></div> <div class="MsoNoSpacing"> <b><br /> Kerugian yang diberikan sistem basis data terdistribusi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Kompleksitas manajemen </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Kontrol integritas lebih sulit </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Biaya pengembangan </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Potensi sumber kesalahan program (bug) yang lebih besar</span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Peningkatan waktu proses <i>(overhead)</i></span><i><span lang="IN"> </span></i></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Keamanan </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Sulitnya standarisasi </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Menambah kebutuhan penyimpanan </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Lebih sulit dalam mengatur lingkungan data</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b>Struktur dari database terdistribusi<o:p></o:p></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Sistem database terdistribusi terdiri dari kumpulan tempat, masing-masing memelihara sistem database lokalnya, masing-masing tempat dapat memproses transaksi lokal. </div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Beberapa konfigurasi dari sistem database terdistribusi:</div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo9; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Fully connected Network</div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo9; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Partially connected Network</div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo9; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Tree connected Network</div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo9; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Star network</div> <div class="MsoNoSpacing" style="margin-left: 72.0pt; mso-list: l0 level2 lfo9; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Ring network<br /> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><br /></div> <div class="MsoNoSpacing"> <br /> <div class="MsoNoSpacing"> <b>Fully connected Network<o:p></o:p></b></div> </div> </div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXsuMD68eBufhmg7FhZCE1ruR6aEViLSOEwaX5qIO3rm4kYCjNuOP0-Lr7tKNHEgD5zob5W2AZJUORCgZ3p3xwrXgFtgtjUDV3rARwcOBDIdM0osllJDJaerFxj4Aadg8rKIUf4Fz-9T4/s1600/Basis+3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="133" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXsuMD68eBufhmg7FhZCE1ruR6aEViLSOEwaX5qIO3rm4kYCjNuOP0-Lr7tKNHEgD5zob5W2AZJUORCgZ3p3xwrXgFtgtjUDV3rARwcOBDIdM0osllJDJaerFxj4Aadg8rKIUf4Fz-9T4/s1600/Basis+3.png" width="320" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg12ACbTOMd_YVQ7Wjoe86pwqyqzSTJhhKfBOVKJ-3PCKmpvLKB3-wUppfVWnBH_HMv0COPpB_EdnGTMxd5wA19RMawkQYnucPsi94_lc4bAcocuoKXfhkBDGuxruruUvjgCnfG336-Tbs/s1600/basis4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="38" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg12ACbTOMd_YVQ7Wjoe86pwqyqzSTJhhKfBOVKJ-3PCKmpvLKB3-wUppfVWnBH_HMv0COPpB_EdnGTMxd5wA19RMawkQYnucPsi94_lc4bAcocuoKXfhkBDGuxruruUvjgCnfG336-Tbs/s1600/basis4.png" width="320" /></a></div> <br /> <br /> <div class="MsoNoSpacing"> <b>Partially connected Network</b></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjL_lBeMPqIx9K5VwE4eLEIH8L-pmrpgQRmvZARqC_kiIXD6DQP6zfxudILKSz45j_vtsRi23WEq0uEeCvPMl1SQThfaKlt6z-tpp3ChODvcSwVVsZV__hJTA1QeE1gW9hJppMDP27xj1c/s1600/Basis+Data+5.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="232" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjL_lBeMPqIx9K5VwE4eLEIH8L-pmrpgQRmvZARqC_kiIXD6DQP6zfxudILKSz45j_vtsRi23WEq0uEeCvPMl1SQThfaKlt6z-tpp3ChODvcSwVVsZV__hJTA1QeE1gW9hJppMDP27xj1c/s1600/Basis+Data+5.png" width="320" /></a></div> <div class="MsoNoSpacing"> </div> <div class="MsoNormal"> <b>Tree connected Network</b></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0W1HlsA4TaS-D7zQRDg4GZCTGLPPmoXOpl9h1TwwkqJ-X9g9N-G1UpMm_AZm_wRgQjnrXNLK-7_gfZCRE_hXgvtyvWWQTsIRTL6lc2q3_d30hKrxcH-WGe2gBTwM8_uGsnlFgOxAgnIM/s1600/Basis+6.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="217" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0W1HlsA4TaS-D7zQRDg4GZCTGLPPmoXOpl9h1TwwkqJ-X9g9N-G1UpMm_AZm_wRgQjnrXNLK-7_gfZCRE_hXgvtyvWWQTsIRTL6lc2q3_d30hKrxcH-WGe2gBTwM8_uGsnlFgOxAgnIM/s1600/Basis+6.png" width="320" /></a></div> <div class="MsoNormal"> <br /> <div class="MsoNormal"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><b><span lang="IN">Ring Network</span></b></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHQVJJI92F3Cfxi3BbfbtcTPhdlBRz6EPGg0VGL0w2CIDKY12cXgbb5x5Y3r3g0JL4CdmLyIOLBFLuwvMafjxfDHEi0mFRXpF599V61ZHT4ZNmuCoiL-Rl8o1olA4ios24gyj_ePi7_uw/s1600/basis+7.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="207" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHQVJJI92F3Cfxi3BbfbtcTPhdlBRz6EPGg0VGL0w2CIDKY12cXgbb5x5Y3r3g0JL4CdmLyIOLBFLuwvMafjxfDHEi0mFRXpF599V61ZHT4ZNmuCoiL-Rl8o1olA4ios24gyj_ePi7_uw/s1600/basis+7.png" width="320" /></a></div> </div> <br /> <b>Star Network</b><br /> <b><br /></b> <br /> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSWPDBLMDEmgiY4-9FgsadmvWr7BziPceLz8K3_bpfj8cnGPpvXiA-nszEpQ9HhmYd7cGcz-99h_jabRHZRSJxy0l2dRVQZxhvp7oCxLMllh2Dy0bMcyUfkvHyGSzOVRLqtoD09z2j7lY/s1600/Basis+8.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="204" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSWPDBLMDEmgiY4-9FgsadmvWr7BziPceLz8K3_bpfj8cnGPpvXiA-nszEpQ9HhmYd7cGcz-99h_jabRHZRSJxy0l2dRVQZxhvp7oCxLMllh2Dy0bMcyUfkvHyGSzOVRLqtoD09z2j7lY/s1600/Basis+8.png" width="320" /></a></div> <div class="separator" style="clear: both; text-align: center;"> </div> <div class="MsoNormal"> <b>DESAIN BASIS DATA TERDISTRIBUSI<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l2 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Ada beberapa pendekatan yang berkaitan dengan penyimpanan data/tabel dalam sebuah sistem basis data terdistribusi, yaitu </div> <div class="MsoNormal" style="margin-left: 72.0pt;"> 1. Replikasi </div> <div class="MsoNormal" style="margin-left: 72.0pt;"> 2. Fragmentasi </div> <div class="MsoNormal" style="margin-left: 72.0pt;"> 3. Replikasi dan Fragmentasi</div> <div class="MsoNormal"> 1. <b>Replikasi </b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Sistem memelihara sejumlah salinan/duplikat tabel-tabel data. </div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Setiap salinan tersimpan dalam simpul yang berbeda, yang menghasilkan replikasi data</div> <div class="MsoNormal"> 2. <b>Fragmentasi </b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l4 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Data dalam tabel dipilah dan disebar ke dalam sejumlah fragmen.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l4 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Tiap fragmen disimpan di sejumlah simpul yang berbeda-beda.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l4 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Fragmentasi dapat berbentuk fragmentasi horizontal (pemilahan record data) atau fragmentasi vertikal pemilahan field/atribut data)</div> <div class="MsoNormal"> 3. <b>Replikasi dan Fragmentasi </b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Merupakan kombinasi dari replikasi dan fragmentasi.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Data/tabel dipilah dalam sejumlah fragmen.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div> <!--[if !supportLists]--><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Sistem lalu mengelola sejumlah salinan dari masing-masing fragmen tadi di sejumlah simpul.</div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> Keuntungan<span lang="IN"> & kerugian</span> :</div> <div class="MsoNormal">                 1. Ketersediaan yang tinggi.</div> <div class="MsoNormal">                 2. Peningkatan Keparalelan (Increased paralelism)</div> <div class="MsoNormal">                 3. Peningkatan beban pengubahan data (Increased overhead on upate)</div> <div class="MsoNormal">  <b>Fragmentasi Data<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Dapat diterapkan operasi union ataupun operasi natural join.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Contoh </div> <div class="MsoNormal"> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div>                 Tabel nasabah bank dengan struktur dan data sebagai berikut :</div> <div class="MsoNormal">                 <b>nasabah = (no_nas, nama_nas, alamat_nas, kota, saldo_simpan, saldo pinjam)</b></div> <div class="MsoNormal"> <br /> <br /> <div class="MsoNormal"> <b>Fragmentasi Data</b></div> <div class="MsoNormal"> <b><br /></b></div> <div class="MsoNormal"> </div> <div style="direction: ltr; margin-bottom: 0pt; margin-left: 0.38in; margin-top: 7.2pt; text-indent: -0.38in; unicode-bidi: embed; vertical-align: baseline;"> <span style="font-size: x-small;"><span style="color: #330066; font-family: Wingdings;">l</span><span style="font-family: Arial;">Tabel</span><span style="font-family: Arial;"> </span><span style="font-family: Arial;">Nasabah</span></span><span style="font-family: Arial; font-size: 30pt;"> </span></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimF_Eoh2VxaiNPQWJ2xpRy_GclxYoO0iphCbo3u7Z1Ja2QrAnDVqBGFNy40Fe97VsyTyTAdIl845LfWEu9JNBQlolMxo7j_etgtnxiUg7kom4UajRxQsekQ0Btf6zSqJ2mo5EwAyVOai8/s1600/Bais+9.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="140" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimF_Eoh2VxaiNPQWJ2xpRy_GclxYoO0iphCbo3u7Z1Ja2QrAnDVqBGFNy40Fe97VsyTyTAdIl845LfWEu9JNBQlolMxo7j_etgtnxiUg7kom4UajRxQsekQ0Btf6zSqJ2mo5EwAyVOai8/s1600/Bais+9.png" width="320" /></a></div> <div style="direction: ltr; margin-bottom: 0pt; margin-left: 0.38in; margin-top: 7.2pt; text-indent: -0.38in; unicode-bidi: embed; vertical-align: baseline;"> <span style="font-family: Arial; font-size: 30pt;"><br /></span></div> <br /></div> <div class="MsoNormal"> <br /> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l5 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Fragmentasi Horizontal</div> <div class="MsoNormal">                 nasabah1 = <span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">s</span>kota=‘Medan’ (nasabah)</div> <div class="MsoNormal">                 nasabah2 = <span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">s</span>kota=‘Padang’ (nasabah)</div> <div class="MsoNormal"> <b>Fragmentasi Data – Horizontal<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Akan diperoleh 2 buah fragemen </div> <ul style="margin-top: 0cm;" type="circle"> <li class="MsoNormal">                Fragmen Nasabah1</li> <li class="MsoNormal">Fragmen Nasabah2</li> </ul> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l4 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Terapkan operasi union </div> <div class="MsoNormal">                 <b>nasabah = nasabah1 </b><b><span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">È</span> nasabah2 </b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l8 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Fragmentasi Vertikal </div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal">                 nasabah1 = <span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">p</span>no_nas, nama_nas, alamat, kota (nasabah)</div> <div class="MsoNormal">                 nasabah2 = <span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">p</span>no_nas, saldo_simpan (nasabah)</div> <div class="MsoNormal">                 nasabah3 = <span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">p</span>no_nas, saldo_pinjam (nasabah)</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l7 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Replikasi dan Fragmentasi </div> <div class="MsoNormal">                 Upaya untuk replikasi dan fragmentasi data dapat dilakukan sekaligus pada sebuah tabel, yaitu dengan mereplikasi fragmen-fragmen yang telah terbentuk. Misalnya, dalam sebuah sistem terdistribusi terdapat 5 buah simpul S1, S2, S3, S4 dan S5. </div> <div class="MsoNormal">                 Kita dapat memilah tabel nasabah sesuai dengan kota dimana nasabah mengajukan permohonan menjadi nasabah1, nasabah2 dan nasabah3.</div> <div class="MsoNormal">                 Kemudian dengan pertimbangan tertentu, fr agmen nasabah1 disimpan di simpul S1, S2 dan S3. lalu fragmen nasabah2 disimpan disimpul S3 dan S4 dan fragmen nasabah3 disimpan di simpul S1 dan S3.</div> <div class="MsoNormal"> <b><br /></b></div> <div class="MsoNormal"> <b>PEMROSESAN QU</b><b><span lang="IN">E</span>RY DALAM BASIS DATA TERDISTRIBUSI<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;"><br /></span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Dalam sistem terpusat, kriteria utama untuk mengetahui cost dari sebuah strategi query adalah jumlah/waktu akses ke disk.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Faktor-fakor yang perlu dipertimbangkan:</div> <div class="MsoNormal">                 1. Biaya/waktu untuk transmisi data</div> <div class="MsoNormal">                 2. Potensi peningkatan karena adanya sejumlah simpul yang dapat melaksanakan query secara paralel.</div> <div class="MsoNormal"> <b><br /></b></div> <div class="MsoNormal"> <b>Transformasi Query<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;"><br /></span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;"><br /></span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jika tabel telah direplikasi  atau difragmentasi atau sekaligus direplikasi dan fragmentasi maka kita dapat memenuhi query tersebut dengan memilih salah satu simpul tempat suatu tabel berada kemudian mengeksekusi qury.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jika tabel tidak direplikasi atau difragmentasi, pemilihan simpul akan didasarkan pada simpul yang memberikan ongkos transmisi data yang paling rendah.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jika tabel difragmentasi dan ditempatkan di berbagai simpul yang berbeda, maka kita harus melakukan operasi Join atau Union untuk merekonstruksi isi seluruh ini disamping tergantung pada query, juga tergantung pada jenis fragmentasi yang diterapkan terhadap tabel yang terlibat dalam query.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jika fragmentasi yang dilakukan horizontal maka operasi Union dapat dilakukan.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jika fragmentasi vertikal dan query menghendaki penayangan semua atribut maka operasi Natural Join yang harus digunakan.</div> <div class="MsoNormal"> <b>Contoh :<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l10 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Tabel Mahasiswa </div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l10 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Ekspresi Standar dari query :</div> <div class="MsoNormal"> <b>                                </b><b><span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">s</span>kota = ‘Bandung (mahasiswa) </b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo10; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jika tabel mahasiswa difragmentasi   secara horizontal di dua fragmen (diberi nama mahasiswa1 dan mahasiswa2) sehingga tabel mahasiswa sesungguhnya merupakan hasil operasi Union dari keduanya.</div> <div class="MsoNormal">                                  <b>mahasiswa1 </b><b><span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">È</span> mahasiswa2</b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l2 level1 lfo11; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Maka query di atas dapat kita translasi menjadi :</div> <div class="MsoNormal"> <b>                </b><b><span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">s</span>kota=‘Bandung’ (mahasiswa1 </b><b><span style="font-family: Symbol; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Symbol;">È</span> mahasiswa2)</b> </div> <div class="MsoNormal"> <br /></div> </div> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a><br /> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><b><br /></b> <br /> <div class="separator" style="clear: both; text-align: center;"> </div>

Basis Data Terdistribusi

l   Teknologi database cenderung membentuk suatu konfigurasi sistem pengolahan data yang terpusat. l   Secara teor e tis datab a se dapa...

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Backup dan Recovery Basis Data

<br /> <div class="MsoNormal"> Beberapa panyebab kerusakan atau kegagalan transaksi/operasi adalah:</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b>Aliran listrik putus</b>, yang dapat mengakibatkan hilangnya informasi yang ada di memori utama dan register.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b>Kesalahan operator (human error)</b>, dimana operator (manusia) melakukan kesalahan operasi yang tidak disengaja.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b>Kesalahan perangkat lunak</b>, yang dapat mengakibatkan hasil pengolahan (akhir/antara) menjadi tidak benar, informasi yang disajikan ke user salah, dan basis data menjadi tidak konsisten.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b>Disk rusak</b>, yang dapat mengakibatkan hilangnya informasi  atau rusaknya basis data yang ada di dalam disk.</div> <div class="MsoNormal"> <b>Pada bab ini akan dibahas dua jenis operasi terhadap basis data dengan fungsi yang berlawanan tapi memiliki ketergantungan satu sama lain.</b></div> <div class="MsoNormal"> <b>Jenis-jenis kerusakan/kegagalan pada DBMS<o:p></o:p></b></div> <ol start="1" style="margin-top: 0cm;" type="1"> <li class="MsoNormal"><b><span lang="IN">Kegagalan Transaksi (<i>Transaction Failure</i>)</span></b><span lang="IN"> </span></li> </ol> <div class="MsoNormal"> <span lang="IN">Ada beberapa jenis kesalahan/ error yang dapat menyebabkan sebuah transaksi menjadi gagal:</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l4 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: "Wingdings 2"; mso-bidi-font-family: "Wingdings 2"; mso-fareast-font-family: "Wingdings 2";">¤<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Kesalahan logika (Logical Error)</span></b><span lang="IN">, di mana program/ sistem tidak dapat melanjutkan eksekusi normalnya karena adanya kondisi internal t</span>e<span lang="IN">rtentu seperti masukan yang salah/ rusak, data tidak tersedia, nilai data diluar batas domain yang diperbolehkan (<i>overflow</i>), logika program yang tidak tepat (<i>bugs</i>) atau batas sumber daya sistem (<i>resource</i>) seperti memori  habis.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l4 level2 lfo3; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: "Wingdings 2"; mso-bidi-font-family: "Wingdings 2"; mso-fareast-font-family: "Wingdings 2";">¤<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Kesalahan sistem (System Error)</span></b><span lang="IN">, dimana program/ sistem telah memasuki kondisi yang tidak diharapkan seperti terjadinya <i>deadlock </i>, sebagai hasil dari tidak tereksekusinya program/ sistem secara normal</span>. </div> <div class="MsoListParagraph" style="mso-list: l1 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->2.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><b> </b><b><span lang="IN">Kerusakan sistem (System Crash)</span></b><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 70.9pt; mso-list: l4 level1 lfo3; tab-stops: list 70.9pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: "Wingdings 2"; mso-bidi-font-family: "Wingdings 2"; mso-fareast-font-family: "Wingdings 2";">¤<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><i> </i><i><span lang="IN">Hardware </span></i><span lang="IN">macet (<i>hang</i>), menyebabkan isi media penyimpanan sementara (volatile storage) hilang.</span><span lang="IN"> </span></div> <div class="MsoListParagraph" style="mso-list: l1 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]-->3.<span style="font-family: 'Times New Roman'; font-size: 7pt;">       </span><!--[endif]--><b> </b><b><span lang="IN">Kegagalan/ kerusakan Disk (<i>Disk Failure</i>)</span></b><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 70.9pt; mso-list: l4 level1 lfo3; tab-stops: list 49.65pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: "Wingdings 2"; mso-bidi-font-family: "Wingdings 2"; mso-fareast-font-family: "Wingdings 2";">¤<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Adanya/ terjadinya <i>bad sector </i>atau disk macet pada saat berlangsungnya operasi I/O ke disk.</span><span lang="IN"> </span></div> <div class="MsoNormal"> <b>       BACKUP<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <b><span lang="IN">Disamping menunjukkan salah satu jenis operasi yang penting dalam sebuah sistem basis data, istilah <i>backup </i>dapat pula merujuk pada objek dari operasi tersebut. </span><o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <b><span lang="IN">Sebagai objek, <i>backup </i>adalah salinan dari data. </span><o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <b><span lang="IN">Data di sini </span><o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l0 level2 lfo4; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-bidi-font-weight: bold; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">tidak hanya meliputi data pada level pemakai akhir/ <i>enduser </i></span><o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l0 level2 lfo4; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-bidi-font-weight: bold; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">tetapi juga bisa mencakup bagian-bagian penting dari basis data secara keseluruhan, seperti file-file kontrol (meta data) ataupun file-file log.</span><o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <span lang="IN">Ditinjau dari objeknya, backup dapat dikelompokkan kedalam:</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <b>1. </b><b><span lang="IN">Backup fisik (<i>physical backup</i>)</span></b><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Adalah salinan fisik file-file basis data seperti tabel-tabel data, file kontrol, file log. Backup fisik dapat dihasilkan dari pengeksekusian program utilitas yang disediakan oleh DBMS yang bersangkutan ataupun program utilitas yang disediakan oleh sistem operasi (<i>Operating System</i>) dimana DBMS itu berada.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <b>2. </b><b><span lang="IN">Backup lojik (<i>logical backup</i>)</span></b><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Backup lojik kita dapatkan dari pembentukan file-file /objek yang berisi perintah (bisa berupa teks bahasa SQL ataupun perintah biner) yang jika dieksekusi dapat mengembalikan basis data ke kondisi semula. Backup lojik hanya dapat dihasilkan dari pengeksekusian program utilitas khusus yang disediakan oleh DBMS yang bersangkutan.</span></div> <div class="MsoNormal"> <span lang="IN">Berdasarkan waktu pelaksanaan atau strateginya, ada dua jenis operasi backup yang dapat kita pilih , yaitu:</span><span lang="IN"> </span></div> <ol start="1" style="margin-top: 0cm;" type="1"> <li class="MsoNormal"><b><span lang="IN">Backup Statis</span></b><span lang="IN">, di mana backup dilakukan dengan terlebih dahulu menonaktifkan basis data secara keseluruhan.</span><span lang="IN"> </span></li> <li class="MsoNormal"><b><span lang="IN">Backup Dinamis, </span></b><span lang="IN">di mana backup dilakukan tanpa penonaktifan basis data sehingga user tetap bisa bekerja. </span></li> </ol> <div class="MsoNormal"> <b>Remote Backup<o:p></o:p></b></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> DBMS yang tersentralisasi maupun client-server hanya menekankan pada pembendaan lokasi pemrosesan <span lang="IN">tetapi lokasi data tetap pada satu lokasi saja.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> Kondisi ini akan menimbulkan masalah jika suatu saat terjadi kebakaran, bencana alam, aksi terorisme, dll.</div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span lang="IN">Sebuah alternatif adalah dengan menjalankan pengolahan transaksi pada sebuah situs yang disebut sebagai situs utama/ primer, tetapi dengan memiliki sebuah situs untuk <i>backup</i> jarak jauh (<i>remote backup</i>), dimana semua data disitus utama direplikasi. </span></div> <div class="MsoNormal" style="margin-left: 36.0pt;"> <span lang="IN">Situs remote backup ini harus disinkronisasi dengan situs primer begitu terjadi perubahan pada situs primer yaitu dengan mengupayakan sinkronisasi dengan mengirimkan semua record log dari situs primer ke remote backup</span><span lang="IN"> </span></div> <div class="MsoNormal"> <span lang="IN">Berikut ini adalah contoh dari arsitektur adanya situs <i>remote backup </i>bagi sebuah situs primer:</span><span lang="IN"> </span><br /> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilq2yEz2McKSRkxfrELo0NE4qvi4_-yvjR5lZ8ZwaB2S23g-sf8oOwQfYtZcUZ7_dTkIsSih2-scieD1L3sEZ-7VrroGmGmLzRz1pYY_nUA4mppkQ4UMv7t2N095t8xp39dilfkYnpYzA/s1600/Untitled.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><img border="0" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilq2yEz2McKSRkxfrELo0NE4qvi4_-yvjR5lZ8ZwaB2S23g-sf8oOwQfYtZcUZ7_dTkIsSih2-scieD1L3sEZ-7VrroGmGmLzRz1pYY_nUA4mppkQ4UMv7t2N095t8xp39dilfkYnpYzA/s1600/Untitled.png" width="640" /><span lang="IN"><br /></span> <br /> <span lang="IN"></span><br /> <div class="MsoNormal"> <span lang="IN"><span lang="IN">Ketika situs primer mengalami kerusakan maka situs <i>remote backup</i> akan segera mengambil alih pemrosesan. Beberapa isu yang perlu kita perhatikan pada saat merancang sebuah sistem dengan remote backup adalah:</span><span lang="IN"> </span></span></div> <span lang="IN"> </span><br /> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l4 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span lang="IN"><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Pendeteksian kerusakan</span></b><span lang="IN"> </span></span></div> <span lang="IN"> </span> <br /> <div class="MsoNormal"> <span lang="IN"><span lang="IN">Kerusakan saluran komunikasi dapat saja menyebabkan situs <i>remote backup</i> berkesimpulan bahwa telah terjadi kerusakan pada situs primer. Untuk menghindari problem ini kita harus menerapkan beberapa saluran (<i>link</i>) komunikasi yang independen antara kedua situs.</span><span lang="IN"> </span></span></div> <span lang="IN"> </span> <br /> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l7 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span lang="IN"><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Pemindahan kontrol</span></b><span lang="IN"> </span></span></div> <span lang="IN"> </span> <br /> <div class="MsoNormal"> <span lang="IN"><span lang="IN">Ketika situs primer mengalami kerusakan, situs backup akan mengambil alih pemrosesan dan menjadi situs primer yang baru.</span><span lang="IN"> </span></span></div> <span lang="IN"> </span> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l1 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span lang="IN"><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Waktu untuk pemulihan</span></b><span lang="IN"> </span></span></div> <span lang="IN"> <div class="MsoNormal"> <span lang="IN">Konfigurasi <i>hot-spare </i>dapat membuat proses pengalihan kontrol menjadi lebih cepat  (hampir instant). Pada konfigurasi ini, situs remote backup secara terus menerus memproses isi file log untuk aksi redo begitu record file log tersebut diterima dan kemudian menerapkannya secara lokal.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l2 level1 lfo4; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Waktu untuk commit</span></b><span lang="IN"> </span></div> <div class="MsoNormal"> <span lang="IN">Sebuah transaksi harus tidak dinyatakan ter-commit sebelum record-record log-nya telah diterima situs backup-nya.</span><span lang="IN"> </span></div> <div class="MsoNormal"> <b><br /></b> <b>RECOVERY<o:p></o:p></b><br /> <b><br /></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l5 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Operasi recovery adalah operasi untuk mengembalikan kondisi database sebelum terjadi kesalahan atau kerusakan.</div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l5 level1 lfo5; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Jenis-jenis operasi recovery:</div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l5 level2 lfo5; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">RECOVERY BERBASIS FILE LOG</span><span lang="IN"> </span></b></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l5 level2 lfo5; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">RECOVERY BERBASIS </span>TIME LINE</b></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l5 level2 lfo5; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">RECOVERY BERBASIS </span>SHADOW PAGE</b></div> <div class="MsoNormal"> <b><span lang="IN"><br /></span></b> <b><span lang="IN">RECOVERY BERBASIS FILE LOG</span><o:p></o:p></b><br /> <b><span lang="IN"><br /></span></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">File log merupakan sarana yang umum digunakan untuk merekam terjadinya perubahan-perubahan terhadap basis data. </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">File log ini berisi record-record log yang berkolerasi dengan semua operasi perubahan pada basis data.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Terdapat  beberapa jenis record-record log yang nantinya akan terlibat dalam mekanisme recovery.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Sebuah record log untuk menunjukkan sebuah operasi penulisan ke basis data, akan memiliki field-field seperti berikut ini:</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Pengidentifikasi Transaksi (Transaction identifier)</span></b><span lang="IN">, yang merupakan nilai unik untuk mengidentifikasi transaksi yang menjalankan operasi <b>write</b>.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Pengidentifikasi data (Data-item identifier), </span></b><span lang="IN"> yang merupakan nilai unik untuk identifikasi item data yang ditulis. Umumnya nilai ini juga menunjukkan lokasi fisik disk dari item data tersebut.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Nilai lama (old value), </span></b><span lang="IN">yang merupakan nilai item data sebelum operasi <b>write</b> dijalankan.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l3 level1 lfo6; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Nilai baru (new value), </span></b><span lang="IN">yang merupakan nilai item data setelah operasi write dijalankan.</span><span lang="IN"> </span></div> <div class="MsoNormal"> <span lang="IN">Sebuah record log untuk menunjukkan sebuah operasi penulisan ke basis data, akan memiliki field-field seperti berikut ini:</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Pengidentifikasi Transaksi (Transaction identifier)</span></b><span lang="IN">, yang merupakan nilai unik untuk mengidentifikasi transaksi yang menjalankan operasi <b>write</b>.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Pengidentifikasi data (Data-item identifier), </span></b><span lang="IN"> yang merupakan nilai unik untuk identifikasi item data yang ditulis. Umumnya nilai ini juga menunjukkan lokasi fisik disk dari item data tersebut.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Nilai lama (old value), </span></b><span lang="IN">yang merupakan nilai item data sebelum operasi <b>write</b> dijalankan.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l0 level1 lfo7; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><b><span lang="IN">Nilai baru (new value), </span></b><span lang="IN">yang merupakan nilai item data setelah operasi write dijalankan.</span><span lang="IN"> </span></div> <div class="MsoNormal"> <span lang="IN">Beberapa jenis-jenis record file log yang menunjukkan operasi-operasi penting terhadap basis data:</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">< T_i <b>start</b>> menunjukan adanya sebuah transaksi T_itelah dimulai.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">< T_i , X_j , V₁ , V₂ > yang menunjukkan transaksi T_i telah menjalankan operasi write terhadap item data X_j.X_jmula-mula bernilai V₁sebelum operasi tersebut dan kemudian bernilai V₂setelah operasi <b>write</b> tersebut.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">< T_i <b>commit </b>> yang menunjukkan transaksi T_itelah direkam sempurna (di-commit)</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">< T_i <b>abort </b>> yang menunjukkan transaksi T_itelah dibatalkan.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l9 level1 lfo8; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Teknik-teknik recovery berbasis log file</div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l9 level2 lfo8; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Teknik File Log dengan <b>Penundaan Pengubahan </b><i>(Incremental Log With Deferred Updates)</i></span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 72.0pt; mso-list: l9 level2 lfo8; tab-stops: list 72.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Teknik File Log dengan <b>Pengubahan Langsung </b><i>(Incremental Log With Immediate Updates)</i></span><span lang="IN"> </span><br /> <span lang="IN"><i><br /></i></span></div> <div class="MsoNormal"> <b><i><span lang="IN">Incremental Log With Deferred Updates</span><o:p></o:p></i></b></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l8 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Teknik ini menjamin keatomikan transaksi dengan merekam semua perubahan basis data ke dalam file log, tetapi menunda eksekusi semua operasi penulisan (write) dalam sebuah transaksi hingga transaksi tersebut barada dalam keadaan ter-<i>commit </i>secara parsial.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l8 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Ketika sebuah transaksi telah ter-commit secara parsial, informasi pada file log yang berhubungan dengan transaksi tersebut akan digunakan untuk mengeksekusi operasi <b>write </b>yang tertunda. Jika sistem tersebut macet (crash) sebelum transaksi selesai dikerjakan, atau jika transaksi tersebut dibatalkan, maka informasi dalam file log ini dengan mudah dapat diabaikan.</span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l8 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->T<span lang="IN">eknik ini </span>hanya membutuhkan <span lang="IN">nilai baru (<i>New Value</i>) dari item yang terlibat dalam operasi <b>write.</b></span><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l8 level1 lfo9; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Ilustrasi transfer dari rekening A ke rekening B sebesar Rp. 100000,- dan penarikan dari rekening C sebesar Rp. 200000,-</div> <div class="MsoNormal"> <br /> <span lang="IN">T₀:          <b>read(A)</b></span><span lang="IN"> </span></div> <div class="MsoNormal"> <span lang="IN">A </span><span lang="IN" style="font-family: Wingdings; mso-ansi-language: IN; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Wingdings;">ß</span><span lang="IN"> A – 100000</span><span lang="IN"> </span></div> <div class="MsoNormal"> <b><span lang="IN">write(A)</span></b><span lang="IN"> </span></div> <div class="MsoNormal"> <b><span lang="IN">read(B)</span></b><span lang="IN"> </span></div> <div class="MsoNormal"> <span lang="IN">B </span><span lang="IN" style="font-family: Wingdings; mso-ansi-language: IN; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Wingdings;">ß</span><span lang="IN"> B + 100000</span><span lang="IN"> </span></div> <div class="MsoNormal"> <b><span lang="IN">write(B)</span></b><br /> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a> <span lang="IN">T₁:          <b>read(C)</b></span></div> <div class="MsoNormal"> <span lang="IN">C </span><span lang="IN" style="font-family: Wingdings; mso-ansi-language: IN; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-char-type: symbol; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin; mso-symbol-font-family: Wingdings;">ß</span><span lang="IN"> C – 200000</span><span lang="IN"> </span></div> <div class="MsoNormal"> <b><span lang="IN">write(C)</span></b><span lang="IN"> </span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l10 level1 lfo10; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;"><br /></span> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Transaksi-transaksi tersebut dieksekusi secara serial dengan urutan <span lang="IN">T₀baru kemudian T₁dan nilai saldo awal untuk rekening A, B, dan C berturut-turut adalah 1 juta, 2 juta, dan 500 ribu rupiah. </span><br /> <span lang="IN"><br /></span></div> <div class="MsoNormal"> <b><span lang="IN">Log                                             Basis data</span></b><span lang="IN"><br /></span><br /> <span lang="IN">< T₀ <b>start </b>> </span><br /> <span lang="IN"><br /></span> <span lang="IN">< T_0,A, 900000 ></span><br /> < T_0,B, 2100000 ><br /> <span lang="IN">< T₀<b>commit</b> ></span><span lang="IN">                                      </span><span lang="IN">A = 900000</span><span lang="IN"> </span><br /> <span lang="IN">                                                   B =  2100000</span><b><span lang="IN"> </span></b><br /> <span lang="IN">< T</span>₁ <b><span lang="IN">start </span></b><span lang="IN">>                                     <br /> </span><span lang="IN">< T</span>₁_{<span lang="IN">, </span>}<span lang="IN">C, 300000 ></span><span lang="IN">< T</span>₁<b><span lang="IN">commit</span></b><span lang="IN"> >                     </span><span lang="IN">C = 300000</span></div> <div class="MsoNormal"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a></div> <div class="MsoNormal"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span lang="IN"><br /></span></div> <div class="MsoNormal" style="margin-left: 36.0pt; mso-list: l6 level1 lfo11; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">l<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Skema recovery ini menjalankan sebuah prosedur <i>recovery </i>jika ada kegagalan sistem, yaitu</span> operasi <span lang="IN">Redo (T_i), yang membuat semua nilai item data yang diubah transaksi T_ike nilai-nilai yang baru.</span><br /> <span lang="IN"><br /></span> <span lang="IN"></span><br /> <div class="MsoNoSpacing"> <span lang="IN"><span lang="IN">Log</span><span lang="IN"> </span><span lang="IN">Basis data</span><span lang="IN"> </span></span></div> <span lang="IN"> <div class="MsoNoSpacing"> <span lang="IN">< T₀ start >                                          </span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T_0,A, 900000 ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T_0,B, 2100000 ></span><span lang="IN">  </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T₀commit ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">                                                                </span>                <span lang="IN">A = 900000</span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">                                                                </span>                <span lang="IN">B =  2100000</span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN"> </span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T₀ start >                                          </span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T_0,C, 300000 ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T₀commit ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">                                                                </span>                <span lang="IN">C = 300000</span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <b><i><span lang="IN">Incremental Log With Immediate Updates</span><o:p></o:p></i></b></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Mekanisme <i>recovery </i>dengan pengubahan segera/langsung membuat tindakan-tindakan perubahan ke basis data di dalam transaksi langsung dilakukan terhadap basis data tersebut kendati transaksi tersebut masih berlangsung.</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l1 level1 lfo1; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Perubahan ke basis data untuk transaksi yang sedang aktif semacam ini disebut dengan perubahan tak sempurna (<i>uncommitted modifications</i>)</span>.</div> <div class="MsoNoSpacing"> Membutuhkan nilai baru dan nilai lama.</div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l2 level1 lfo2; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]-->Ilustrasi:</div> <div class="MsoNoSpacing"> <b><span lang="IN">Log                                 </span></b><b style="text-indent: -18pt;"><span lang="IN">Basis data</span></b><b style="text-indent: -18pt;"><span lang="IN">                                                      </span>             </b></div> <div class="MsoNoSpacing"> <span lang="IN">< T₀ <b>start </b>>                                          </span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T_0,A, 1000000 , <b>900000</b> >             </span><span lang="IN"></span><span style="text-indent: -18pt;">A = 900000</span></div> <div class="MsoNoSpacing"> <span lang="IN">< T_0,B, 2000000 , <b>2100000</b> >            </span><span lang="IN"></span><span style="text-indent: -18pt;">B =</span><span style="text-indent: -18pt;"> </span><span style="text-indent: -18pt;"> </span><span style="text-indent: -18pt;">2100000</span></div> <div class="MsoNoSpacing"> <span lang="IN">                                                                                </span>                </div> <div class="MsoNoSpacing"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><span lang="IN">                                                                                </span>                </div> <div class="MsoNoSpacing"> <span lang="IN">< T₀<b>commit</b> ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T₀ <b>start </b>>                                          </span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <span lang="IN">< T_0,C, </span>500000, <b><span lang="IN">300000</span></b><span lang="IN"> >            </span><span lang="IN"></span><span style="text-indent: -18pt;">C = 300000</span></div> <div class="MsoNoSpacing"> <span lang="IN">                                                                                </span>                </div> <div class="MsoNoSpacing"> <span lang="IN">< T₀<b>commit</b> ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <br /></div> <div class="MsoNoSpacing"> <span lang="IN">Jika terjadi kegagalan sistem, skema <i>recovery</i> ini memakai dua prosedur berikut ini:</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt;"> <span lang="IN">Undo(T_i), yang merekam kembali nilai semua item data yang diubah  oleh transaksi T_ike nilai awalnya.</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="text-indent: 36.0pt;"> <span lang="IN">Redo(T_i), yang membuat semua nilai item data yang diubah oleh transaksi T_ike nilai barunya.</span></div> <div class="MsoNoSpacing"> <a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=6668295035605216251" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span lang="IN">Setelah terjadi kegagalan sistem/ basis data, skema recovery ini akan melihat isi dari file log untuk mengetahui transaksi mana saja yang akan diulangi dan transaksi mana saja yang akan dibatalkan. Keduanya dapat diketahui dengan menggunakan aturan sebagai berikut:</span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Transaksi T_iharus dikembalikan ke kondisi awalnya (<b>undo</b>) jika dalam file log terdapat record < T_i<b>start </b>> dan tidak ada record < T_i<b>commit</b> ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing" style="margin-left: 36.0pt; mso-list: l0 level1 lfo3; tab-stops: list 36.0pt; text-indent: -18.0pt;"> <!--[if !supportLists]--><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;">¨<span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><!--[endif]--><span lang="IN">Transaksi T_iharus dituntaskan (<b>redo</b>) jika dalam file log terdapat record < T_i<b>start </b>> dan record < T_i<b>commit</b> ></span><span lang="IN"> </span></div> <div class="MsoNoSpacing"> <br /></div> </span><br /> <span lang="IN"><br /></span> <span lang="IN"><br /></span> <span lang="IN"><br /></span> <span lang="IN"><br /></span> <span lang="IN"><br /></span> <span lang="IN"><br /></span> <span lang="IN"><br /></span> <span lang="IN"><br /></span></div> <div class="MsoNormal"> <br /></div> </span></div> <div class="MsoNormal"> <!--[if gte vml 1]><v:shapetype id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f"> <v:stroke joinstyle="miter"/> <v:formulas> <v:f eqn="if lineDrawn pixelLineWidth 0"/> <v:f eqn="sum @0 1 0"/> <v:f eqn="sum 0 0 @1"/> <v:f eqn="prod @2 1 2"/> <v:f eqn="prod @3 21600 pixelWidth"/> <v:f eqn="prod @3 21600 pixelHeight"/> <v:f eqn="sum @0 0 1"/> <v:f eqn="prod @6 1 2"/> <v:f eqn="prod @7 21600 pixelWidth"/> <v:f eqn="sum @8 21600 0"/> <v:f eqn="prod @7 21600 pixelHeight"/> <v:f eqn="sum @10 21600 0"/> </v:formulas> <v:path o:extrusionok="f" gradientshapeok="t" o:connecttype="rect"/> <o:lock v:ext="edit" aspectratio="t"/> </v:shapetype><v:shape id="Picture_x0020_1" o:spid="_x0000_i1025" type="#_x0000_t75" style='width:468.75pt;height:126pt;visibility:visible;mso-wrap-style:square'> <v:imagedata src="file:///C:\Users\user\AppData\Local\Temp\msohtmlclip1\01\clip_image001.png" o:title="" croptop="28481f" cropbottom="12230f" cropleft="7496f" cropright="1731f"/> </v:shape><![endif]--><!--[if !vml]--><!--[endif]--></div>

Backup dan Recovery Basis Data

Beberapa panyebab kerusakan atau kegagalan transaksi/operasi adalah: ¨   Aliran listrik putus , yang dapat mengakibatkan hilangnya infor...

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