65 lines
4.7 KiB
HTML
65 lines
4.7 KiB
HTML
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<meta name="DC.Title" content="Add referential constraints" />
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<meta name="abstract" content="You can add referential constraints on physical files with no more than one member. A referential constraint is a file-level attribute; therefore, you can create the constraint before the member exists." />
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<title>Add referential constraints</title>
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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 referential constraints</h1>
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<div><p>You can add referential constraints on physical files with no more
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than one member. A referential constraint is a file-level attribute; therefore,
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you can create the constraint before the member exists.</p>
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</div>
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<div>
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<ul class="ullinks">
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<li class="ulchildlink"><strong><a href="rbaforzahfrch.htm">Before you add referential constraints</a></strong><br />
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Before you can add referential constraints, you must make sure that you meet some conditions.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfrci.htm">Define the parent file in a referential constraint</a></strong><br />
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A parent file must be a physical file with a maximum of one member. You can create a new file or use an existing file when you define the parent file.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfrcj.htm">Define the dependent file in a referential constraint</a></strong><br />
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A dependent file must be a physical file with a maximum of one member. You can create a dependent file as you do any physical file or use an existing file.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfrck.htm">Specify referential constraint rules</a></strong><br />
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Referential constraints allow you to specify rules that you want the system to enforce when you delete or update records.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfrcf.htm">Details: Add referential constraints</a></strong><br />
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Here is a list of limitations that apply to referential constraints.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfrcg.htm">Details: Avoid constraint cycles</a></strong><br />
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A <em>constraint cycle</em> is a sequence of constraint relationships
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in which a descendent of a parent file becomes a parent to the original parent
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file. You can use constraint cycles in a DB2 Universal Database™ for iSeries™ database,
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however, you should avoid using them.</li>
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</ul>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbaforzahfrca.htm" title="These topics discuss how to use referential constraints in your database to ensure that it contains only valid data.">Ensure data integrity with referential constraints</a></div>
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