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<meta name="abstract" content="The delete and update rules that you specify when you create a constraint apply to parent key changes. The database enforces a no-action rule on the insert and update operations to the foreign key in order to maintain referential integrity. The system enforces this rule on the insert and update operations to the foreign key to ensure that the value of every non-null foreign key matches the value of the parent key." />
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<h1 class="topictitle1">Foreign key enforcement</h1>
<div><p>The delete and update rules that you specify when
you create a constraint apply to parent key changes. The database enforces
a no-action rule on the insert and update operations to the foreign key in
order to maintain referential integrity. The system enforces this rule on
the insert and update operations to the foreign key to ensure that the value
of every non-null foreign key matches the value of the parent key.</p>
<p>The system returns a referential constraint violation if a matching parent
key does not exist for the new foreign key value, and does not insert or update
the dependent record. </p>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbaforzahfrcp.htm" title="The input/output (I/O) access for files that are associated with established and enabled constraints varies. It depends on whether the file contains the parent key or foreign key in the constraint relationship. The system enforces referential integrity enforcement on all parent and dependent file I/O requests.">Referential integrity enforcement</a></div>
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