linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       If a foreign key, the referenced table; else zero
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>confupdtype</structfield> <type>char</type>
      </para>
      <para>
       Foreign key update action code:
       <literal>a</literal> = no action,
       <literal>r</literal> = restrict,
       <literal>c</literal> = cascade,
       <literal>n</literal> = set null,
       <literal>d</literal> = set default
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>confdeltype</structfield> <type>char</type>
      </para>
      <para>
       Foreign key deletion action code:
       <literal>a</literal> = no action,
       <literal>r</literal> = restrict,
       <literal>c</literal> = cascade,
       <literal>n</literal> = set null,
       <literal>d</literal> = set default
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>confmatchtype</structfield> <type>char</type>
      </para>
      <para>
       Foreign key match type:
       <literal>f</literal> = full,
       <literal>p</literal> = partial,
       <literal>s</literal> = simple
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conislocal</structfield> <type>bool</type>
      </para>
      <para>
       This constraint is defined locally for the relation.  Note that a
       constraint can be locally defined and inherited simultaneously.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>coninhcount</structfield> <type>int2</type>
      </para>
      <para>
       The number of direct inheritance ancestors this constraint has.
       A constraint with
       a nonzero number of ancestors cannot be dropped nor renamed.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>connoinherit</structfield> <type>bool</type>
      </para>
      <para>
       This constraint is defined locally for the relation.  It is a
       non-inheritable constraint.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conperiod</structfield> <type>bool</type>
      </para>
      <para>
       This constraint is defined with <literal>WITHOUT OVERLAPS</literal>
       (for primary keys and unique constraints) or <literal>PERIOD</literal>
       (for foreign keys).
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>conkey</structfield> <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>)