Doc: Update FDW documentation about direct foreign table modification.

Etsuro Fujita · Etsuro Fujita · commit 879b69be2936 · 2019-09-18T18:50:03.000+09:00
1. Commit 7086be6 should have documented the limitation that the direct modification is disabled when WCO constraints are present, but didn't, which is definitely my fault. Update the documentation (Postgres 9.6 onwards). 2. Commit fc22b66 should have documented the limitation that the direct modification is disabled when generated columns are defined, but didn't. Update the documentation (Postgres 12 onwards). Author: Etsuro Fujita Discussion: https://postgr.es/m/CAPmGK14AYCPunLb6TRz1CQsW5Le01Z2ox8LSOKH0P-cOVDcQRA%40mail.gmail.com
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
@@ -724,9 +724,11 @@ IsForeignRelUpdatable (Relation rel);
      row-by-row approach is necessary, but it can be inefficient.  If it is
      possible for the foreign server to determine which rows should be
      modified without actually retrieving them, and if there are no local
-     triggers which would affect the operation, then it is possible to
-     arrange things so that the entire operation is performed on the remote
-     server.  The interfaces described below make this possible.
+     structures which would affect the operation (row-level local triggers
+     or <literal>WITH CHECK OPTION</literal> constraints from parent views),
+     then it is possible to arrange things so that the entire operation is
+     performed on the remote server.  The interfaces described below make
+     this possible.
     </para>
 
     <para>
