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<h1 class="topictitle1">Precautions to take when coding trigger programs</h1>
<div><p>Trigger programs can be very powerful. But you must take caution
when coding trigger programs. </p>
<p>Be careful when designing trigger programs that access a system resource,
such as a tape drive. For instance, a trigger program that copies record changes
to tape media can be useful, but the program itself cannot detect if the tape
drive is ready or if it contains the correct tape. You must take these kinds
of resource issues into considerations when designing trigger programs.</p>
<p>In addition, use read triggers with extreme caution. Using
a read trigger causes a trigger to be called for every record that is read.
During a query, this means that triggers can be called many times as records
are processed multiple times by the query. This can impact system performance.</p>
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<ul class="ullinks">
<li class="ulchildlink"><strong><a href="rbafotrgfn.htm">Functions to use with care in trigger programs</a></strong><br />
Some control language (CL) commands and functions are not recommended in a trigger program and need to be carefully considered if they are to be used.</li>
<li class="ulchildlink"><strong><a href="rbafotrgncmd.htm">Commands, statements, and operations that you cannot use in trigger programs</a></strong><br />
A trigger program cannot include some commands, statements, and operations.</li>
</ul>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbaforzahftrb2.htm" title="These topics discuss recommendations, precautions, and error messages for trigger programs. Information about monitoring and commitment control is also included.">Other important information about working with triggers</a></div>
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