<type>int2[]</type>
       (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attnum</structfield>)
      </para>
      <para>
       If a table constraint (including foreign keys, but not constraint
       triggers), list of the constrained columns
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>confkey</structfield> <type>int2[]</type>
       (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attnum</structfield>)
      </para>
      <para>
       If a foreign key, list of the referenced columns
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conpfeqop</structfield> <type>oid[]</type>
       (references <link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       If a foreign key, list of the equality operators for PK = FK comparisons
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conppeqop</structfield> <type>oid[]</type>
       (references <link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       If a foreign key, list of the equality operators for PK = PK comparisons
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conffeqop</structfield> <type>oid[]</type>
       (references <link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       If a foreign key, list of the equality operators for FK = FK comparisons
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>confdelsetcols</structfield> <type>int2[]</type>
       (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attnum</structfield>)
      </para>
      <para>
       If a foreign key with a <literal>SET NULL</literal> or <literal>SET
       DEFAULT</literal> delete action, the columns that will be updated.
       If null, all of the referencing columns will be updated.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conexclop</structfield> <type>oid[]</type>
       (references <link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       If an exclusion constraint or <literal>WITHOUT OVERLAPS</literal>
       primary key/unique constraint, list of the per-column exclusion operators.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conbin</structfield> <type>pg_node_tree</type>
      </para>
      <para>
       If a check constraint, an internal representation of the
       expression.  (It's recommended to use
       <function>pg_get_constraintdef()</function> to extract the definition of
       a check constraint.)
      </para></entry>
     </row>
    </tbody>
   </tgroup>
  </table>

  <para>
   In the case of an exclusion constraint, <structfield>conkey</structfield>
   is only useful for constraint elements that are simple column references.
   For other cases, a zero appears in <structfield>conkey</structfield>
   and the associated index must be consulted to discover the expression
   that is constrained.  (<structfield>conkey</structfield> thus has the
   same contents as <link linkend="catalog-pg-index"><structname>pg_index</structname></link>.<structfield>indkey</structfield>