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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="infoschema-constraint-column-usage"></a>31.10.<code class="literal">constraint_column_usage</code></h2></div></div></div>
<p> The view <code class="literal">constraint_column_usage</code> identifies all
columns in the current database that are used by some constraint.
Only those columns are shown that are contained in a table owned
the current user. For a check constraint, this view identifies the
columns that are used in the check expression. For a foreign key
constraint, this view identifies the columns that the foreign key
references. For a unique or primary key constraint, this view
identifies the constrained columns.
</p>
<div class="table">
<a name="id694685"></a><p class="title"><b>Table31.8.<code class="literal">constraint_column_usage</code> Columns</b></p>
<div class="table-contents"><table summary="constraint_column_usage Columns" border="1">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Name</th>
<th>Data Type</th>
<th>Description</th>
</tr></thead>
<tbody>
<tr>
<td><code class="literal">table_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the database that contains the table that contains the
column that is used by some constraint (always the current
database)
</td>
</tr>
<tr>
<td><code class="literal">table_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the schema that contains the table that contains the
column that is used by some constraint
</td>
</tr>
<tr>
<td><code class="literal">table_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the table that contains the column that is used by some
constraint
</td>
</tr>
<tr>
<td><code class="literal">column_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the column that is used by some constraint
</td>
</tr>
<tr>
<td><code class="literal">constraint_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the database that contains the constraint (always the current database)</td>
</tr>
<tr>
<td><code class="literal">constraint_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the schema that contains the constraint</td>
</tr>
<tr>
<td><code class="literal">constraint_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the constraint</td>
</tr>
</tbody>
</table></div>
</div>
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