diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index 52407a7..91c2dd4 100644
*** a/doc/src/sgml/information_schema.sgml
--- b/doc/src/sgml/information_schema.sgml
*************** ORDER BY c.ordinal_position;
*** 3211,3216 ****
--- 3211,3229 ----
      </tbody>
     </tgroup>
    </table>
+ 
+   <note>
+    <para>
+     The SQL standard requires constraint names to be unique within a
+     schema;  <productname>PostgreSQL</productname>, however, does not
+     enforce this restriction.  If duplicate-named constraints are
+     stored in the same <productname>PostgreSQL</productname> schema, a
+     standard-compliant query that expects to return one row might
+     return several, one for each matching constraint stored in the
+     specified schema.
+    </para>
+   </note>
+ 
   </sect1>
  
   <sect1 id="infoschema-role-column-grants">