95 lines
5.9 KiB
HTML
95 lines
5.9 KiB
HTML
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<meta name="DC.Title" content="Add triggers" />
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<meta name="abstract" content="This topic shows how to add triggers to a database file." />
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<title>Add triggers</title>
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<body id="rbaforzahftrn"><a name="rbaforzahftrn"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Add triggers</h1>
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<div><p>This topic shows how to add triggers to a database file.</p>
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<p>To add a trigger, follow these steps:</p>
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<ol><li>Ensure that you have the proper authority and the file has the proper
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data capabilities.</li>
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<li><p><img src="./delta.gif" alt="Start of change" />Use one of the following methods to associate the
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trigger program with a specific database file: <img src="./deltaend.gif" alt="End of change" /></p>
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<ul><li><img src="./delta.gif" alt="Start of change" />Use iSeries™ Navigator to create a new file or edit the
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properties of an existing file.<img src="./deltaend.gif" alt="End of change" /></li>
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<li>Use the Add Physical File Trigger (ADDPFTRG) command.</li>
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<li>Use the CREATE TRIGGER SQL statement.</li>
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</ul>
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</li>
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</ol>
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<div class="note"><span class="notetitle">Note:</span> If the trigger program resides in QTEMP library, the trigger program
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cannot be associated with a physical file.</div>
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<p><img src="./delta.gif" alt="Start of change" />After you have created the association between the trigger
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program and the file, the system calls the trigger program when a change or
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read operation is initiated against the database file, a member of the file,
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and any logical file created over the physical file.<img src="./deltaend.gif" alt="End of change" /></p>
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<p><img src="./delta.gif" alt="Start of change" />You can associate a maximum of 300 triggers with one database
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file. Each insert, delete, or update operation can call multiple triggers
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before and after the operation occurs. Each read operation can call multiple
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triggers after the operation occurs. This topic shows how to add a trigger
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to a file.<img src="./deltaend.gif" alt="End of change" /></p>
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<p><img src="./delta.gif" alt="Start of change" />You can associate a maximum of three triggers with one logical
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file. That is, you can create one INSTEAD OF trigger per insert, update, or
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delete operation. The trigger is called instead of performing the operation.<img src="./deltaend.gif" alt="End of change" /></p>
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<p>The number of triggers called after a read operation that is issued by
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a query might not be equal to the number of records that are actually returned.
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This is because the query might have read a different number of records, causing
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a trigger to be called for each read operation, before returning the correct
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number of records.</p>
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<p>An SQL update operation involves a simultaneous read operation followed
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by a write operation. Read triggers are not run for SQL update operations.
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An update trigger should be specified to cover this read operation followed
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by a write operation.</p>
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<div class="section" id="rbaforzahftrn__rbaforzahftru"><a name="rbaforzahftrn__rbaforzahftru"><!-- --></a><h4 class="sectiontitle">Required authorities and data capabilities
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for triggers</h4><div class="p">These required authorities are listed here:<ul><li>Object management or Alter authority to the file</li>
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<li>Object operational authority to the file</li>
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<li>Read data rights to the file</li>
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<li>Update data rights and Object operational authority to the file if CRTPFTRG
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ALWREPCHG(*YES) is specified</li>
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<li>Execute authority to the file's library</li>
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<li>Execute authority to the trigger program</li>
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<li>Execute authority to the trigger program's library</li>
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</ul>
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</div>
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<div class="p">The file must have appropriate data capabilities before you add
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a trigger: <ul><li>CRTPF ALWUPD(*NO) conflicts with *UPDATE Trigger</li>
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<li>CRTPF ALWDLT(*NO) conflicts with *DELETE Trigger</li>
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</ul>
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</div>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbaforzahftra.htm" title="A trigger is a set of actions that run automatically when a specified change or read operation is performed on a specified database file. On iSeries, you define a set of trigger actions in any supported high-level language.">Trigger automatic events in your database</a></div>
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</div>
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<div class="relref"><strong>Related reference</strong><br />
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<div><a href="../cl/addpftrg.htm">Add Physical File Trigger (ADDPFTRG) command</a></div>
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</div>
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</div>
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