g
   to the table that the trigger is defined on.)  Second, triggers can
   be defined to fire on multiple events in
   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> (e.g., <TT
CLASS="LITERAL"
>ON INSERT OR
   UPDATE</TT
>), whereas the SQL standard only allows one.  If a
   trigger is defined to fire on multiple events, it is represented as
   multiple rows in the information schema, one for each type of
   event.  As a consequence of these two issues, the primary key of
   the view <TT
CLASS="LITERAL"
>tr