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id="toc-Triggers_in_DBMS-sublist" class="vector-toc-list"> <li id="toc-Oracle" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Oracle"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Oracle</span> </div> </a> <ul id="toc-Oracle-sublist" class="vector-toc-list"> <li id="toc-Schema-level_triggers" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Schema-level_triggers"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1.1</span> <span>Schema-level triggers</span> </div> </a> <ul id="toc-Schema-level_triggers-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-System-level_triggers" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#System-level_triggers"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1.2</span> <span>System-level triggers</span> </div> </a> <ul id="toc-System-level_triggers-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Microsoft_SQL_Server" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Microsoft_SQL_Server"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2</span> <span>Microsoft SQL Server</span> </div> </a> <ul id="toc-Microsoft_SQL_Server-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-PostgreSQL" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#PostgreSQL"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>PostgreSQL</span> </div> </a> <ul id="toc-PostgreSQL-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Firebird" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Firebird"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.4</span> <span>Firebird</span> </div> </a> <ul id="toc-Firebird-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-MySQL/MariaDB" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#MySQL/MariaDB"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.5</span> <span>MySQL/MariaDB</span> </div> </a> <ul id="toc-MySQL/MariaDB-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-IBM_DB2_LUW" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#IBM_DB2_LUW"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.6</span> <span>IBM DB2 LUW</span> </div> </a> <ul id="toc-IBM_DB2_LUW-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-SQLite" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#SQLite"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.7</span> <span>SQLite</span> </div> </a> <ul id="toc-SQLite-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-XML_databases" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#XML_databases"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.8</span> <span>XML databases</span> </div> </a> <ul id="toc-XML_databases-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Row_and_statement_level_triggers" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Row_and_statement_level_triggers"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Row and statement level triggers</span> </div> </a> <button aria-controls="toc-Row_and_statement_level_triggers-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Row and statement level triggers subsection</span> </button> <ul id="toc-Row_and_statement_level_triggers-sublist" class="vector-toc-list"> <li id="toc-After_-_statement-level_trigger" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#After_-_statement-level_trigger"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>After - statement-level trigger</span> </div> </a> <ul id="toc-After_-_statement-level_trigger-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Before_each_-_row-level_trigger" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Before_each_-_row-level_trigger"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Before each - row-level trigger</span> </div> </a> <ul id="toc-Before_each_-_row-level_trigger-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Before_-_statement-level_trigger" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Before_-_statement-level_trigger"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Before - statement-level trigger</span> </div> </a> <ul id="toc-Before_-_statement-level_trigger-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Database trigger</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 26 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-26" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">26 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A7%D9%84%D9%85%D8%AD%D8%B1%D9%83_%D9%81%D9%8A_%D9%82%D9%88%D8%A7%D8%B9%D8%AF_%D8%A7%D9%84%D8%A8%D9%8A%D8%A7%D9%86%D8%A7%D8%AA" title="المحرك في قواعد البيانات – Arabic" lang="ar" hreflang="ar" data-title="المحرك في قواعد البيانات" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Veril%C9%99nl%C9%99r_bazas%C4%B1_triggeri" title="Verilənlər bazası triggeri – Azerbaijani" lang="az" hreflang="az" data-title="Verilənlər bazası triggeri" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Trigger" title="Trigger – Catalan" lang="ca" hreflang="ca" data-title="Trigger" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Trigger_(datab%C3%A1ze)" title="Trigger (databáze) – Czech" lang="cs" hreflang="cs" data-title="Trigger (databáze)" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Datenbanktrigger" title="Datenbanktrigger – German" lang="de" hreflang="de" data-title="Datenbanktrigger" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Trigger_(base_de_datos)" title="Trigger (base de datos) – Spanish" lang="es" hreflang="es" data-title="Trigger (base de datos)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%85%D8%AD%D8%B1%DA%A9_%D9%BE%D8%A7%DB%8C%DA%AF%D8%A7%D9%87_%D8%AF%D8%A7%D8%AF%D9%87" title="محرک پایگاه داده – Persian" lang="fa" hreflang="fa" data-title="محرک پایگاه داده" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/D%C3%A9clencheur" title="Déclencheur – French" lang="fr" hreflang="fr" data-title="Déclencheur" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%8D%B0%EC%9D%B4%ED%84%B0%EB%B2%A0%EC%9D%B4%EC%8A%A4_%ED%8A%B8%EB%A6%AC%EA%B1%B0" title="데이터베이스 트리거 – Korean" lang="ko" hreflang="ko" data-title="데이터베이스 트리거" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Trigger_(basi_di_dati)" title="Trigger (basi di dati) – Italian" lang="it" hreflang="it" data-title="Trigger (basi di dati)" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Kisituo" title="Kisituo – Swahili" lang="sw" hreflang="sw" data-title="Kisituo" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Trigeris_(DBPS)" title="Trigeris (DBPS) – Latvian" lang="lv" hreflang="lv" data-title="Trigeris (DBPS)" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Trigger_(adatb%C3%A1zisok)" title="Trigger (adatbázisok) – Hungarian" lang="hu" hreflang="hu" data-title="Trigger (adatbázisok)" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D3%A8%D0%B3%D3%A9%D0%B3%D0%B4%D0%BB%D0%B8%D0%B9%D0%BD_%D1%81%D0%B0%D0%BD%D0%B3%D0%B8%D0%B9%D0%BD_%D1%82%D1%80%D0%B8%D0%B3%D0%B3%D0%B5%D1%80" title="Өгөгдлийн сангийн триггер – Mongolian" lang="mn" hreflang="mn" data-title="Өгөгдлийн сангийн триггер" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Trigger" title="Trigger – Dutch" lang="nl" hreflang="nl" data-title="Trigger" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%87%E3%83%BC%E3%82%BF%E3%83%99%E3%83%BC%E3%82%B9%E3%83%88%E3%83%AA%E3%82%AC" title="データベーストリガ – Japanese" lang="ja" hreflang="ja" data-title="データベーストリガ" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Databaseutl%C3%B8ser" title="Databaseutløser – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Databaseutløser" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Wyzwalacz" title="Wyzwalacz – Polish" lang="pl" hreflang="pl" data-title="Wyzwalacz" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Gatilho_(banco_de_dados)" title="Gatilho (banco de dados) – Portuguese" lang="pt" hreflang="pt" data-title="Gatilho (banco de dados)" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A2%D1%80%D0%B8%D0%B3%D0%B3%D0%B5%D1%80_(%D0%B1%D0%B0%D0%B7%D1%8B_%D0%B4%D0%B0%D0%BD%D0%BD%D1%8B%D1%85)" title="Триггер (базы данных) – Russian" lang="ru" hreflang="ru" data-title="Триггер (базы данных)" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/Trigeri" title="Trigeri – Serbian" lang="sr" hreflang="sr" data-title="Trigeri" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Her%C3%A4te" title="Heräte – Finnish" lang="fi" hreflang="fi" data-title="Heräte" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Trigger_(databasteknik)" title="Trigger (databasteknik) – Swedish" lang="sv" hreflang="sv" data-title="Trigger (databasteknik)" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Trigger" title="Trigger – Turkish" lang="tr" hreflang="tr" data-title="Trigger" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A2%D1%80%D0%B8%D0%B3%D0%B5%D1%80_(%D0%B1%D0%B0%D0%B7%D0%B8_%D0%B4%D0%B0%D0%BD%D0%B8%D1%85)" title="Тригер (бази даних) – Ukrainian" lang="uk" hreflang="uk" data-title="Тригер (бази даних)" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E8%A7%A6%E5%8F%91%E5%99%A8_(%E6%95%B0%E6%8D%AE%E5%BA%93)" title="触发器 (数据库) – Chinese" lang="zh" hreflang="zh" data-title="触发器 (数据库)" data-language-autonym="中文" data-language-local-name="Chinese" 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searchaux" style="display:none">Database code that executes after certain events on a table</div> <p>A <b>database trigger</b> is <a href="/wiki/Procedural_code" class="mw-redirect" title="Procedural code">procedural code</a> that is automatically executed in response to certain <a href="/wiki/Event_(computing)" title="Event (computing)">events</a> on a particular <a href="/wiki/Table_(database)" title="Table (database)">table</a> or <a href="/wiki/View_(database)" class="mw-redirect" title="View (database)">view</a> in a <a href="/wiki/Database" title="Database">database</a>. The trigger is mostly used for maintaining the <a href="/wiki/Database_integrity" class="mw-redirect" title="Database integrity">integrity</a> of the information on the database. For example, when a new record (representing a new worker) is added to the employees table, new records should also be created in the tables of the taxes, vacations and salaries. Triggers can also be used to log historical data, for example to keep track of employees' previous salaries. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Triggers_in_DBMS">Triggers in DBMS</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=1" title="Edit section: Triggers in DBMS"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Below follows a series of descriptions of how some popular <a href="/wiki/DBMS" class="mw-redirect" title="DBMS">DBMS</a> support triggers. </p> <div class="mw-heading mw-heading3"><h3 id="Oracle">Oracle</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=2" title="Edit section: Oracle"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In addition to triggers that fire (and execute <a href="/wiki/PL/SQL" title="PL/SQL">PL/SQL</a> code) when data is modified, <a href="/wiki/Oracle_Database" title="Oracle Database">Oracle 10g</a> supports triggers that fire when schema-level objects (that is, tables) are modified and when user logon or logoff events occur. </p> <div class="mw-heading mw-heading4"><h4 id="Schema-level_triggers">Schema-level triggers</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=3" title="Edit section: Schema-level triggers"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>After Creation</li> <li>Before Alter</li> <li>After Alter</li> <li>Before Drop</li> <li>After Drop</li> <li>Before Insert</li></ul> <p>The four main types of triggers are: </p> <ol><li>Row-level trigger: This gets executed before or after <i>any column value of a row</i> changes.</li> <li>Column-level trigger: This gets executed before or after the <i>specified column</i> changes.</li> <li>For each row type: This trigger gets executed once for each row of the <a href="/wiki/Result_set" title="Result set">result set</a> affected by an insert/update/delete.</li> <li>For each statement type: This trigger gets executed only once for the entire result set, but also fires each time the statement is executed.</li></ol> <div class="mw-heading mw-heading4"><h4 id="System-level_triggers">System-level triggers</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=4" title="Edit section: System-level triggers"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>From <a href="/wiki/Oracle8i" class="mw-redirect" title="Oracle8i">Oracle 8i</a>, database events - logons, logoffs, startups - can fire Oracle triggers.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Microsoft_SQL_Server">Microsoft SQL Server</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=5" title="Edit section: Microsoft SQL Server"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>MS SQL Server supports trigger for DML and DDL statement plus special trigger "logon". </p><p>The scope of DDL triggers can be a database (CREATE TRIGGER name ON DATABASE ...) or the entire SQL Server instance (CREATE TRIGGER name ON ALL SERVER). When you use the entire instance, you can capture all events executed on commands that have server-level scope as well as any commands that have database-level scope in the SQL instance. </p><p>A list of all available firing events in Microsoft SQL Server for DDL triggers is available on <a href="/wiki/Microsoft_Docs" title="Microsoft Docs">Microsoft Docs</a>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>Performing conditional actions in DML triggers (or testing data following modification) is done through accessing the pseudo tables (temporary ones) Inserted and Deleted tables. DML trigger are always "FOR EACH STATEMENT" but can be code at row event ("FOR EACH ROW") using a cursor on the inserted/deleted pseudo tables. </p> <div class="mw-heading mw-heading3"><h3 id="PostgreSQL">PostgreSQL</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=6" title="Edit section: PostgreSQL"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Introduced support for triggers in 1997. The following functionality in <a href="/wiki/SQL:2003" title="SQL:2003">SQL:2003</a> was previously not implemented in PostgreSQL: </p> <ul><li>SQL allows triggers to fire on updates to specific columns; As of version 9.0 of PostgreSQL this feature is also implemented in PostgreSQL.</li> <li>The standard allows the execution of a number of SQL statements other than <a href="/wiki/Select_(SQL)" title="Select (SQL)">SELECT</a>, <a href="/wiki/Insert_(SQL)" title="Insert (SQL)">INSERT</a>, <a href="/wiki/Update_(SQL)" title="Update (SQL)">UPDATE</a>, such as CREATE TABLE as the triggered action. This can be done through creating a stored procedure or function to call CREATE TABLE.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup></li></ul> <p>Synopsis: </p> <div class="mw-highlight mw-highlight-lang-postgresql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="k">name</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">BEFORE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">AFTER</span><span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">event</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="mf">...</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="p">}</span> <span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">FOR</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">EACH</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">ROW</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">STATEMENT</span><span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="p">]</span> <span class="w"> </span><span class="k">EXECUTE</span><span class="w"> </span><span class="k">PROCEDURE</span><span class="w"> </span><span class="n">funcname</span><span class="w"> </span><span class="p">(</span><span class="w"> </span><span class="n">arguments</span><span class="w"> </span><span class="p">)</span> </pre></div> <div class="mw-heading mw-heading3"><h3 id="Firebird">Firebird</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=7" title="Edit section: Firebird"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Firebird_(database_server)" title="Firebird (database server)">Firebird</a> supports multiple row-level, BEFORE or AFTER, INSERT, UPDATE, DELETE (or any combination of thereof) triggers per table, where they are always "in addition to" the default table changes, and the order of the triggers relative to each other can be specified where it would otherwise be ambiguous (POSITION clause.) Triggers may also exist on views, where they are always "instead of" triggers, replacing the default updatable view logic. (Before version 2.1, triggers on views deemed updatable would run in addition to the default logic.) </p><p>Firebird does not raise mutating table exceptions (like Oracle), and triggers will by default both nest and recurse as required (SQL Server allows nesting but not recursion, by default.) Firebird's triggers use NEW and OLD context variables (not Inserted and Deleted tables,) and provide UPDATING, INSERTING, and DELETING flags to indicate the current usage of the trigger. </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="err">{</span><span class="k">CREATE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">RECREATE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">CREATE</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="k">ALTER</span><span class="err">}</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="k">FOR</span><span class="w"> </span><span class="err">{</span><span class="k">table</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">view</span><span class="w"> </span><span class="n">name</span><span class="err">}</span> <span class="w"> </span><span class="p">[</span><span class="n">ACTIVE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">INACTIVE</span><span class="p">]</span> <span class="w"> </span><span class="err">{</span><span class="k">BEFORE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">AFTER</span><span class="err">}</span> <span class="w"> </span><span class="err">{</span><span class="k">INSERT</span><span class="w"> </span><span class="p">[</span><span class="k">OR</span><span class="w"> </span><span class="k">UPDATE</span><span class="p">]</span><span class="w"> </span><span class="p">[</span><span class="k">OR</span><span class="w"> </span><span class="k">DELETE</span><span class="p">]</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">UPDATE</span><span class="w"> </span><span class="p">[</span><span class="k">OR</span><span class="w"> </span><span class="k">INSERT</span><span class="p">]</span><span class="w"> </span><span class="p">[</span><span class="k">OR</span><span class="w"> </span><span class="k">DELETE</span><span class="p">]</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DELETE</span><span class="w"> </span><span class="p">[</span><span class="k">OR</span><span class="w"> </span><span class="k">UPDATE</span><span class="p">]</span><span class="w"> </span><span class="p">[</span><span class="k">OR</span><span class="w"> </span><span class="k">INSERT</span><span class="p">]</span><span class="w"> </span><span class="err">}</span> <span class="w"> </span><span class="p">[</span><span class="k">POSITION</span><span class="w"> </span><span class="n">n</span><span class="p">]</span><span class="w"> </span><span class="k">AS</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="p">....</span> <span class="k">END</span> </pre></div> <p>As of version 2.1, Firebird additionally supports the following database-level triggers: </p> <ul><li>CONNECT (exceptions raised here prevent the connection from completing)</li> <li>DISCONNECT</li> <li>TRANSACTION START</li> <li>TRANSACTION COMMIT (exceptions raised here prevent the transaction from committing, or preparing if a two-phase commit is involved)</li> <li>TRANSACTION ROLLBACK</li></ul> <p>Database-level triggers can help enforce multi-table constraints, or emulate <a href="/wiki/Materialized_view" title="Materialized view">materialized views</a>. If an exception is raised in a TRANSACTION COMMIT trigger, the changes made by the trigger so far are rolled back and the client application is notified, but the transaction remains active as if COMMIT had never been requested; the client application can continue to make changes and re-request COMMIT. </p><p>Syntax for database triggers: </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="err">{</span><span class="k">CREATE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">RECREATE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">CREATE</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="k">ALTER</span><span class="err">}</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="n">name</span> <span class="w"> </span><span class="p">[</span><span class="n">ACTIVE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">INACTIVE</span><span class="p">]</span><span class="w"> </span><span class="k">ON</span> <span class="w"> </span><span class="err">{</span><span class="k">CONNECT</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DISCONNECT</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">TRANSACTION</span><span class="w"> </span><span class="k">START</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">TRANSACTION</span><span class="w"> </span><span class="k">COMMIT</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">TRANSACTION</span><span class="w"> </span><span class="k">ROLLBACK</span><span class="err">}</span> <span class="w"> </span><span class="p">[</span><span class="k">POSITION</span><span class="w"> </span><span class="n">n</span><span class="p">]</span><span class="w"> </span><span class="k">AS</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="p">.....</span> <span class="k">END</span> </pre></div> <div class="mw-heading mw-heading3"><h3 id="MySQL/MariaDB"><span id="MySQL.2FMariaDB"></span>MySQL/MariaDB</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=8" title="Edit section: MySQL/MariaDB"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Limited support for triggers in the MySQL/MariaDB <a href="/wiki/DBMS" class="mw-redirect" title="DBMS">DBMS</a> was added in the 5.0 version of MySQL, launched in 2005.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>As of version 8.0, they allow for DDL (Data Definition Language) triggers and for DML (Data Manipulation Language) triggers. They also allow either type of DDL trigger (AFTER or BEFORE) to be used to define triggers. They are created by using the clause <i>CREATE TRIGGER</i> and deleted by using the clause <i>DROP TRIGGER</i>. The statement called upon an event happens is defined after the clause <i>FOR EACH ROW</i>, followed by a keyword (<i>SET</i> or <i>BEGIN</i>), which indicates whether what follows is an expression or a statement respectively.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="IBM_DB2_LUW">IBM DB2 LUW</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=9" title="Edit section: IBM DB2 LUW"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>IBM DB2 for distributed systems known as DB2 for LUW (LUW means <b>L</b>inux, <b>U</b>nix, <b>W</b>indows) supports three trigger types: Before trigger, After trigger and Instead of trigger. Both statement level and row level triggers are supported. If there are more triggers for same operation on table then firing order is determined by trigger creation data. Since version 9.7 IBM DB2 supports <a href="/w/index.php?title=Autonomous_transactions&action=edit&redlink=1" class="new" title="Autonomous transactions (page does not exist)">autonomous transactions</a>.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>Before trigger is for checking data and deciding if operation should be permitted. If exception is thrown from before trigger then operation is aborted and no data are changed. In DB2 before triggers are read only — you can't modify data in before triggers. After triggers are designed for post processing after requested change was performed. After triggers can write data into tables and unlike some<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Avoid_weasel_words" class="mw-redirect" title="Wikipedia:Avoid weasel words"><span title="The material near this tag possibly uses too vague attribution or weasel words. (June 2012)">which?</span></a></i>]</sup> other databases you can write into any table including table on which trigger operates. Instead of triggers are for making views writeable. </p><p>Triggers are usually programmed in <a href="/wiki/SQL_PL" title="SQL PL">SQL PL</a> language. </p> <div class="mw-heading mw-heading3"><h3 id="SQLite">SQLite</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=10" title="Edit section: SQLite"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="p">[</span><span class="n">TEMP</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">TEMPORARY</span><span class="p">]</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="p">[</span><span class="k">IF</span><span class="w"> </span><span class="k">NOT</span><span class="w"> </span><span class="k">EXISTS</span><span class="p">]</span><span class="w"> </span><span class="p">[</span><span class="n">database_name</span><span class="w"> </span><span class="p">.]</span><span class="w"> </span><span class="k">trigger_name</span> <span class="p">[</span><span class="k">BEFORE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">AFTER</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">INSTEAD</span><span class="w"> </span><span class="k">OF</span><span class="p">]</span><span class="w"> </span><span class="err">{</span><span class="k">DELETE</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">INSERT</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">UPDATE</span><span class="w"> </span><span class="p">[</span><span class="k">OF</span><span class="w"> </span><span class="k">column_name</span><span class="w"> </span><span class="p">[,</span><span class="w"> </span><span class="k">column_name</span><span class="p">]...]</span><span class="err">}</span><span class="w"> </span> <span class="k">ON</span><span class="w"> </span><span class="err">{</span><span class="k">table_name</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">view_name</span><span class="err">}</span> <span class="w"> </span><span class="p">[</span><span class="k">FOR</span><span class="w"> </span><span class="k">EACH</span><span class="w"> </span><span class="k">ROW</span><span class="p">]</span><span class="w"> </span><span class="p">[</span><span class="k">WHEN</span><span class="w"> </span><span class="n">condition</span><span class="w"> </span><span class="k">is</span><span class="w"> </span><span class="n">mandatory</span><span class="w"> </span><span class="p">]</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="p">...</span> <span class="k">END</span> </pre></div> <p><a href="/wiki/SQLite" title="SQLite">SQLite</a> only supports row-level triggers, not statement-level triggers. </p><p><a href="/w/index.php?title=Updateable_views&action=edit&redlink=1" class="new" title="Updateable views (page does not exist)">Updateable views</a>, which are not supported in SQLite, can be emulated with INSTEAD OF triggers. </p> <div class="mw-heading mw-heading3"><h3 id="XML_databases">XML databases</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=11" title="Edit section: XML databases"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An example of implementation of triggers in non-relational database can be <a href="/wiki/Sedna_(database)" title="Sedna (database)">Sedna</a>, that provides support for triggers based on <a href="/wiki/XQuery" title="XQuery">XQuery</a>. Triggers in Sedna were designed to be analogous to <a href="/wiki/SQL:2003" title="SQL:2003">SQL:2003</a> triggers, but natively base on XML query and update languages (<a href="/wiki/XPath" title="XPath">XPath</a>, <a href="/wiki/XQuery" title="XQuery">XQuery</a> and XML update language). </p><p>A trigger in Sedna is set on any nodes of an XML document stored in database. When these nodes are updated, the trigger automatically executes XQuery queries and updates specified in its body. For example, the following trigger cancels person node deletion if there are any open auctions referenced by this person: </p> <div class="mw-highlight mw-highlight-lang-xql mw-content-ltr" dir="ltr"><pre><span></span><span class="nt">CREATE</span><span class="w"> </span><span class="err">TRIGGER</span><span class="w"> </span><span class="s2">"trigger3"</span> <span class="w"> </span><span class="err">BEFORE</span><span class="w"> </span><span class="err">DELETE</span> <span class="w"> </span><span class="err">ON</span><span class="w"> </span><span class="err">doc(</span><span class="s2">"auction"</span><span class="p">)/</span><span class="nt">site</span><span class="p">//</span><span class="nt">person</span> <span class="w"> </span><span class="err">FOR</span><span class="w"> </span><span class="err">EACH</span><span class="w"> </span><span class="err">NODE</span> <span class="w"> </span><span class="err">DO</span> <span class="w"> </span><span class="p">{</span> <span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nf">exists</span><span class="p">(</span><span class="nv">$</span><span class="n">WHERE</span><span class="p">//</span><span class="nt">open_auction</span><span class="p">/</span><span class="nt">bidder</span><span class="p">/</span><span class="nt">personref</span><span class="p">/</span><span class="na">@person</span><span class="o">=</span><span class="nv">$</span><span class="n">OLD</span><span class="p">/</span><span class="na">@id</span><span class="p">))</span> <span class="w"> </span><span class="k">then</span><span class="w"> </span><span class="p">(</span><span class="w"> </span><span class="p">)</span> <span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="nv">$</span><span class="n">OLD</span><span class="p">;</span> <span class="w"> </span><span class="p">}</span> </pre></div> <div class="mw-heading mw-heading2"><h2 id="Row_and_statement_level_triggers">Row and statement level triggers</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=12" title="Edit section: Row and statement level triggers"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>To understand how trigger behavior works, you need to be aware of the two main types of triggers; these are Row and Statement level triggers. The distinction between the two is how many times the code within the trigger is executed, and at what time. </p><p>Suppose you have a trigger that is made to be called on an UPDATE to a certain table. Row level triggers would execute once for each row that is affected by the UPDATE. It is important to keep in mind if no rows are affected by the UPDATE command, the trigger <b>will not</b> execute any code within the trigger. Statement level triggers will be called once <b>regardless</b> of how many rows are affected by the UPDATE. Here it is important to note that even if the UPDATE command didn't affect any rows, the code within the trigger will still be executed once. </p><p>Using the BEFORE and AFTER options<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> determine when the trigger is called. Suppose you have a trigger that is called on an INSERT to a certain table. If your trigger is using the BEFORE option, the code within the trigger will be executed before the INSERT into the table occurs. A common use of the BEFORE trigger is to verify the input values of the INSERT, or modify the values accordingly. Now let's say we have a trigger that uses AFTER instead. The code within the trigger is executed after the INSERT happens to the table. An example use of this trigger is creating an audit history of who has made inserts into the database, keeping track of the changes made. When using these options you need to keep a few things in mind. The BEFORE option does <b>not allow</b> you to modify tables, that is why input validation is a practical use. Using AFTER triggers allows you to modify tables such as inserting into an audit history table. </p><p>When creating a trigger to determine if it is statement or row level simply include the FOR EACH ROW clause for a row level, or omit the clause for a statement level. Be cautious of using additional <a href="/wiki/Insert_(SQL)" title="Insert (SQL)">INSERT</a>/<a href="/wiki/Update_(SQL)" title="Update (SQL)">UPDATE</a>/<a href="/wiki/Delete_(SQL)" title="Delete (SQL)">DELETE</a> commands within your trigger, because trigger <a href="/wiki/Recursion_(computer_science)" title="Recursion (computer science)">recursion</a> is possible, causing unwanted behavior. In the examples below each trigger is modifying a different table, by looking at what is being modified you can see some common applications of when different trigger types are used. </p><p>The following is an Oracle syntax example of a row level trigger that is called AFTER an update FOR EACH ROW affected. This trigger is called on an update to a phone book database. When the trigger is called it adds an entry into a separate table named phone_book_audit. Also take note of triggers being able to take advantage of schema objects like sequences,<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> in this example audit_id_sequence.nexVal is used to generate unique <a href="/wiki/Primary_key" title="Primary key">primary keys</a> in the phone_book_audit table. </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="k">REPLACE</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="n">phone_book_audit</span> <span class="w"> </span><span class="k">AFTER</span><span class="w"> </span><span class="k">UPDATE</span><span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="n">phone_book</span><span class="w"> </span><span class="k">FOR</span><span class="w"> </span><span class="k">EACH</span><span class="w"> </span><span class="k">ROW</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="n">phone_book_audit</span><span class="w"> </span> <span class="w"> </span><span class="p">(</span><span class="n">audit_id</span><span class="p">,</span><span class="n">audit_change</span><span class="p">,</span><span class="w"> </span><span class="n">audit_l_name</span><span class="p">,</span><span class="w"> </span><span class="n">audit_f_name</span><span class="p">,</span><span class="w"> </span><span class="n">audit_old_phone_number</span><span class="p">,</span><span class="w"> </span><span class="n">audit_new_phone_number</span><span class="p">,</span><span class="w"> </span><span class="n">audit_date</span><span class="p">)</span><span class="w"> </span> <span class="w"> </span><span class="k">VALUES</span> <span class="w"> </span><span class="p">(</span><span class="n">audit_id_sequence</span><span class="p">.</span><span class="n">nextVal</span><span class="p">,</span><span class="s1">'Update'</span><span class="p">,</span><span class="w"> </span><span class="p">:</span><span class="k">OLD</span><span class="p">.</span><span class="n">last_name</span><span class="p">,</span><span class="w"> </span><span class="p">:</span><span class="k">OLD</span><span class="p">.</span><span class="n">first_name</span><span class="p">,</span><span class="w"> </span><span class="p">:</span><span class="k">OLD</span><span class="p">.</span><span class="n">phone_number</span><span class="p">,</span><span class="w"> </span><span class="p">:</span><span class="k">NEW</span><span class="p">.</span><span class="n">phone_number</span><span class="p">,</span><span class="w"> </span><span class="n">SYSDATE</span><span class="p">);</span> <span class="k">END</span><span class="p">;</span> </pre></div> <p>Now calling an <a href="/wiki/Update_(SQL)" title="Update (SQL)">UPDATE</a> on the phone_book table for people with the last name 'Jones'. </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">UPDATE</span><span class="w"> </span><span class="n">phone_book</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="n">phone_number</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s1">'111-111-1111'</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">last_name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s1">'Jones'</span><span class="p">;</span> </pre></div> <table class="wikitable"> <tbody><tr> <th>Audit_ID</th> <th>Audit_Change</th> <th>F_Name</th> <th>L_Name</th> <th>New_Phone_Number</th> <th>Old_Phone_Number</th> <th>Audit_Date </th></tr> <tr> <td>1</td> <td>Update</td> <td>Jordan</td> <td>Jones</td> <td>111-111-1111</td> <td>098-765-4321</td> <td>02-MAY-14 </td></tr> <tr> <td>2</td> <td>Update</td> <td>Megan</td> <td>Jones</td> <td>111-111-1111</td> <td>111-222-3456</td> <td>02-MAY-14 </td></tr></tbody></table> <p><br /> Notice that the phone_number_audit table is now populated with two entries. This is due to the database having two entries with the last name of 'Jones'. Since the update modified two separate row values, the created trigger was called twice; once after each modification. </p> <div class="mw-heading mw-heading3"><h3 id="After_-_statement-level_trigger">After - statement-level trigger</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=13" title="Edit section: After - statement-level trigger"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An Oracle syntax statement trigger that is called after an UPDATE to the phone_book table. When the trigger gets called it makes an insert into phone_book_edit_history table </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="k">REPLACE</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="n">phone_book_history</span> <span class="w"> </span><span class="k">AFTER</span><span class="w"> </span><span class="k">UPDATE</span><span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="n">phone_book</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="n">phone_book_edit_history</span><span class="w"> </span> <span class="w"> </span><span class="p">(</span><span class="n">audit_history_id</span><span class="p">,</span><span class="w"> </span><span class="n">username</span><span class="p">,</span><span class="w"> </span><span class="n">modification</span><span class="p">,</span><span class="w"> </span><span class="n">edit_date</span><span class="p">)</span><span class="w"> </span> <span class="w"> </span><span class="k">VALUES</span> <span class="w"> </span><span class="p">(</span><span class="n">audit_history_id_sequence</span><span class="p">.</span><span class="n">nextVal</span><span class="p">,</span><span class="w"> </span><span class="k">USER</span><span class="p">,</span><span class="s1">'Update'</span><span class="p">,</span><span class="w"> </span><span class="n">SYSDATE</span><span class="p">);</span> <span class="k">END</span><span class="p">;</span> </pre></div><p> Now doing exactly the same update as the above example, however this time with a statement level trigger. </p><div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">UPDATE</span><span class="w"> </span><span class="n">phone_book</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="n">phone_number</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s1">'111-111-1111'</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">last_name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s1">'Jones'</span><span class="p">;</span> </pre></div> <table class="wikitable"> <tbody><tr> <th>Audit_History_ID</th> <th>Username</th> <th>Modification</th> <th>Edit_Date </th></tr> <tr> <td>1</td> <td>HAUSCHBC</td> <td>Update</td> <td>02-MAY-14 </td></tr></tbody></table> <p>The result shows that the trigger was only called once, even though the update did change two rows. </p> <div class="mw-heading mw-heading3"><h3 id="Before_each_-_row-level_trigger">Before each - row-level trigger</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=14" title="Edit section: Before each - row-level trigger"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>This example demonstrates a BEFORE EACH ROW trigger that modifies the INSERT using a WHEN conditional. If the last name is larger than 10 letters, using the SUBSTR function<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> we change the last_name column value to an abbreviation. </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="k">REPLACE</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="n">phone_book_insert</span> <span class="w"> </span><span class="k">BEFORE</span><span class="w"> </span><span class="k">INSERT</span><span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="n">phone_book</span><span class="w"> </span><span class="k">FOR</span><span class="w"> </span><span class="k">EACH</span><span class="w"> </span><span class="k">ROW</span> <span class="w"> </span><span class="k">WHEN</span><span class="w"> </span><span class="p">(</span><span class="k">LENGTH</span><span class="p">(</span><span class="k">new</span><span class="p">.</span><span class="n">last_name</span><span class="p">)</span><span class="w"> </span><span class="o">></span><span class="w"> </span><span class="mi">10</span><span class="p">)</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="p">:</span><span class="k">new</span><span class="p">.</span><span class="n">last_name</span><span class="w"> </span><span class="p">:</span><span class="o">=</span><span class="w"> </span><span class="n">SUBSTR</span><span class="p">(:</span><span class="k">new</span><span class="p">.</span><span class="n">last_name</span><span class="p">,</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">);</span> <span class="k">END</span><span class="p">;</span> </pre></div> <p>Now performing an INSERT of someone with a large name. </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="n">phone_book</span><span class="w"> </span><span class="k">VALUES</span> <span class="p">(</span><span class="mi">6</span><span class="p">,</span><span class="w"> </span><span class="s1">'VeryVeryLongLastName'</span><span class="p">,</span><span class="w"> </span><span class="s1">'Erin'</span><span class="p">,</span><span class="w"> </span><span class="s1">'Minneapolis'</span><span class="p">,</span><span class="w"> </span><span class="s1">'MN'</span><span class="p">,</span><span class="w"> </span><span class="s1">'989 University Drive'</span><span class="p">,</span><span class="w"> </span><span class="s1">'123-222-4456'</span><span class="p">,</span><span class="w"> </span><span class="mi">55408</span><span class="p">,</span><span class="w"> </span><span class="n">TO_DATE</span><span class="p">(</span><span class="s1">'11/21/1991'</span><span class="p">,</span><span class="w"> </span><span class="s1">'MM/DD/YYYY'</span><span class="p">));</span> </pre></div> <table class="wikitable"> <tbody><tr> <th>Person_ID</th> <th>Last_Name</th> <th>First_Name</th> <th>City</th> <th>State_Abbreviation</th> <th>Address</th> <th>Phone_Number</th> <th>Zip_code</th> <th>DOB </th></tr> <tr> <td>6</td> <td>V</td> <td>Erin</td> <td>Minneapolis</td> <td>MN</td> <td>989 University Drive</td> <td>123-222-4456</td> <td>55408</td> <td>21-NOV-91 </td></tr></tbody></table> <p>The trigger worked as per the result above, modifying the value of the INSERT <b>before</b> it was executed. </p> <div class="mw-heading mw-heading3"><h3 id="Before_-_statement-level_trigger">Before - statement-level trigger</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=15" title="Edit section: Before - statement-level trigger"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Using a BEFORE statement trigger is particularly useful when enforcing database restrictions.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> This example demonstrate how to enforce a restriction upon someone named "SOMEUSER" on the table phone_book. </p> <div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">OR</span><span class="w"> </span><span class="k">REPLACE</span><span class="w"> </span><span class="k">TRIGGER</span><span class="w"> </span><span class="n">hauschbc</span><span class="w"> </span> <span class="w"> </span><span class="k">BEFORE</span><span class="w"> </span><span class="k">INSERT</span><span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="n">SOMEUSER</span><span class="p">.</span><span class="n">phone_book</span> <span class="k">BEGIN</span> <span class="w"> </span><span class="n">RAISE_APPLICATION_ERROR</span><span class="w"> </span><span class="p">(</span> <span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">=></span><span class="w"> </span><span class="o">-</span><span class="mi">20050</span><span class="p">,</span> <span class="w"> </span><span class="n">msg</span><span class="w"> </span><span class="o">=></span><span class="w"> </span><span class="s1">'Error message goes here.'</span><span class="p">);</span> <span class="k">END</span><span class="p">;</span> </pre></div> <p>Now, when "SOMEUSER" is logged in after attempting any INSERT this error message will show: </p> <pre>SQL Error: ORA-20050: Error message goes here. </pre> <p>Custom errors such as this one has a restriction on what the num variable can be defined as. Because of the numerous other pre-defined errors this variable must be in the range of −20000 to −20999. </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=16" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"> <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFNandaBurleson2003" class="citation book cs1">Nanda, Arup; Burleson, Donald K. (2003). "9". In Burleson, Donald K. (ed.). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Gm2hzeWhou0C"><i>Oracle Privacy Security Auditing: Includes Federal Law Compliance with HIPAA, Sarbanes Oxley and the Gramm Leach Bliley Act GLB</i></a>. Oracle in-focus series. Vol. 47. Kittrell, North Carolina: Rampant TechPress. p. 511. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780972751391" title="Special:BookSources/9780972751391"><bdi>9780972751391</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">2018-04-17</span></span>. <q>[...] system-level triggers [...] were introduced in Oracle8i. [...] system-level triggers are fired at specific system events such as logon, logoff, database startup, DDL execution, and servererror [...].</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=9&rft.btitle=Oracle+Privacy+Security+Auditing%3A+Includes+Federal+Law+Compliance+with+HIPAA%2C+Sarbanes+Oxley+and+the+Gramm+Leach+Bliley+Act+GLB&rft.place=Kittrell%2C+North+Carolina&rft.series=Oracle+in-focus+series&rft.pages=511&rft.pub=Rampant+TechPress&rft.date=2003&rft.isbn=9780972751391&rft.aulast=Nanda&rft.aufirst=Arup&rft.au=Burleson%2C+Donald+K.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DGm2hzeWhou0C&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://docs.microsoft.com/en-us/sql/relational-databases/triggers/ddl-events?view=sql-server-ver15">"DDL Events - SQL Server"</a>. 15 March 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=DDL+Events+-+SQL+Server&rft.date=2023-03-15&rft_id=https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fsql%2Frelational-databases%2Ftriggers%2Fddl-events%3Fview%3Dsql-server-ver15&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.postgresql.org/docs/9.0/sql-createtrigger.html">"PostgreSQL: Documentation: 9.0: CREATE TRIGGER"</a>. <i>www.postgresql.org</i>. 8 October 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.postgresql.org&rft.atitle=PostgreSQL%3A+Documentation%3A+9.0%3A+CREATE+TRIGGER&rft.date=2015-10-08&rft_id=https%3A%2F%2Fwww.postgresql.org%2Fdocs%2F9.0%2Fsql-createtrigger.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">MySQL 5.0 Reference Manual. <a rel="nofollow" class="external text" href="https://downloads.mysql.com/docs/refman-5.0-en.pdf">"Triggers. MySQL 5.0 added limited support for triggers"</a>, <i><a href="/wiki/Oracle_Corporation" title="Oracle Corporation">Oracle Corporation</a></i>, Retrieved on 4 March 2020.</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://dev.mysql.com/doc/refman/8.0/en/trigger-syntax.html">"MySQL :: MySQL 8.0 Reference Manual :: 25.3.1 Trigger Syntax and Examples"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=MySQL+%3A%3A+MySQL+8.0+Reference+Manual+%3A%3A+25.3.1+Trigger+Syntax+and+Examples&rft_id=https%3A%2F%2Fdev.mysql.com%2Fdoc%2Frefman%2F8.0%2Fen%2Ftrigger-syntax.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ibm.com/developerworks/data/library/techarticle/dm-0907autonomoustransactions/index.html">"Autonomous transactions"</a>. <i>www.ibm.com</i>. July 30, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.ibm.com&rft.atitle=Autonomous+transactions&rft.date=2009-07-30&rft_id=http%3A%2F%2Fwww.ibm.com%2Fdeveloperworks%2Fdata%2Flibrary%2Ftecharticle%2Fdm-0907autonomoustransactions%2Findex.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://docs.oracle.com/cd/B25329_01/doc/appdev.102/b25108/xedev_triggers.htm">"6 Using Triggers"</a>. <i>docs.oracle.com</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=docs.oracle.com&rft.atitle=6+Using+Triggers&rft_id=https%3A%2F%2Fdocs.oracle.com%2Fcd%2FB25329_01%2Fdoc%2Fappdev.102%2Fb25108%2Fxedev_triggers.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://docs.oracle.com/cd/B12037_01/server.101/b10759/statements_6014.htm">"Oracle's Documentation on Sequences"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20111201225844/http://docs.oracle.com/cd/B12037_01/server.101/b10759/statements_6014.htm">Archived</a> from the original on 2011-12-01.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Oracle%27s+Documentation+on+Sequences&rft_id=http%3A%2F%2Fdocs.oracle.com%2Fcd%2FB12037_01%2Fserver.101%2Fb10759%2Fstatements_6014.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.databasestar.com/oracle-sql-functions/">"Oracle SQL Functions – The Complete List"</a>. December 26, 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Oracle+SQL+Functions+%E2%80%93+The+Complete+List&rft.date=2014-12-26&rft_id=https%3A%2F%2Fwww.databasestar.com%2Foracle-sql-functions%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://docs.oracle.com/cd/B28359_01/appdev.111/b28370/create_trigger.htm">"Database PL/SQL Language Reference"</a>. <i>docs.oracle.com</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=docs.oracle.com&rft.atitle=Database+PL%2FSQL+Language+Reference&rft_id=https%3A%2F%2Fdocs.oracle.com%2Fcd%2FB28359_01%2Fappdev.111%2Fb28370%2Fcreate_trigger.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADatabase+trigger" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Database_trigger&action=edit&section=17" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="http://msdn2.microsoft.com/en-us/library/aa258846(SQL.80).aspx">Microsoft SQL Server DROP TRIGGER</a></li> <li><a rel="nofollow" class="external text" href="http://dev.mysql.com/doc/refman/5.6/en/triggers.html">MySQL Database triggers</a></li> <li><a rel="nofollow" class="external text" href="http://dev.mysql.com/doc/refman/5.6/en/create-trigger.html">MySQL DB Create Triggers</a></li> <li><a rel="nofollow" class="external text" href="http://publib.boulder.ibm.com/infocenter/db2luw/v9/topic/com.ibm.db2.udb.admin.doc/doc/r0000931.htm">DB2 CREATE TRIGGER statement</a></li> <li><a rel="nofollow" class="external text" href="http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_7004.htm#sthref7885">Oracle CREATE TRIGGER</a></li> <li><a rel="nofollow" class="external text" href="http://www.postgresql.org/docs/8.2/static/sql-createtrigger.html">PostgreSQL CREATE TRIGGER</a></li> <li><a rel="nofollow" class="external text" href="http://www.akadia.com/services/ora_mutating_table_problems.html">Oracle Mutating Table Problems with DELETE CASCADE</a></li> <li><a rel="nofollow" class="external text" href="http://www.sqlite.org/lang_createtrigger.html">SQLite Query Language: CREATE TRIGGER</a></li> 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4em"><a href="/wiki/Database" title="Database">Database management systems</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Types</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Object_database" title="Object database">Object-oriented</a> <ul><li><a href="/wiki/Comparison_of_object_database_management_systems" title="Comparison of object database management systems">comparison</a></li></ul></li> <li><a href="/wiki/Relational_database" title="Relational database">Relational</a> <ul><li><a href="/wiki/List_of_relational_database_management_systems" title="List of relational database management systems">list</a></li> <li><a href="/wiki/Comparison_of_relational_database_management_systems" title="Comparison of relational database management systems">comparison</a></li></ul></li> <li><a href="/wiki/Key%E2%80%93value_database" title="Key–value database">Key–value</a></li> <li><a href="/wiki/Column-oriented_DBMS" class="mw-redirect" title="Column-oriented DBMS">Column-oriented</a> <ul><li><a href="/wiki/List_of_column-oriented_DBMSes" title="List of column-oriented DBMSes">list</a></li></ul></li> <li><a href="/wiki/Document-oriented_database" title="Document-oriented database">Document-oriented</a></li> <li><a href="/wiki/Wide-column_store" title="Wide-column store">Wide-column store</a></li> <li><a href="/wiki/Graph_database" title="Graph database">Graph</a></li> <li><a href="/wiki/NoSQL" title="NoSQL">NoSQL</a></li> <li><a href="/wiki/NewSQL" title="NewSQL">NewSQL</a></li> <li><a href="/wiki/In-memory_database" title="In-memory database">In-memory</a> <ul><li><a href="/wiki/List_of_in-memory_databases" title="List of in-memory databases">list</a></li></ul></li> <li><a href="/wiki/Multi-model_database" title="Multi-model database">Multi-model</a> <ul><li><a href="/wiki/Comparison_of_multi-model_databases" title="Comparison of multi-model databases">comparison</a></li></ul></li> <li><a href="/wiki/Cloud_database" title="Cloud database">Cloud</a></li> <li><a href="/wiki/Blockchain-based_database" title="Blockchain-based database">Blockchain-based database</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Database" title="Database">Database</a></li> <li><a href="/wiki/ACID" title="ACID">ACID</a></li> <li><a href="/wiki/Armstrong%27s_axioms" title="Armstrong's axioms">Armstrong's axioms</a></li> <li><a href="/wiki/Codd%27s_12_rules" title="Codd's 12 rules">Codd's 12 rules</a></li> <li><a href="/wiki/CAP_theorem" title="CAP theorem">CAP theorem</a></li> <li><a href="/wiki/Create,_read,_update_and_delete" title="Create, read, update and delete">CRUD</a></li> <li><a href="/wiki/Null_(SQL)" title="Null (SQL)">Null</a></li> 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vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" ><span class="mw-page-title-main">Database trigger</span></div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history mw-ui-icon-wikimedia-wikimedia-history"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-star mw-ui-icon-wikimedia-wikimedia-star"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-wikiText mw-ui-icon-wikimedia-wikimedia-wikiText"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>26 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="mw-portlet mw-portlet-dock-bottom emptyPortlet" id="p-dock-bottom"> <ul> </ul> </div> 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