<productname>Postgres</productname> has various server-side function

interfaces. Server-side functions can be written in SQL, PLPGSQL,

TCL, or C. Trigger functions can be written in any of these

languages. Note that STATEMENT-level trigger events are not supported

in the current version. You can currently specify BEFORE or AFTER on

INSERT, DELETE or UPDATE of a tuple as a trigger event.

languages except SQL. Note that STATEMENT-level trigger events are not

supportedin the current version. You can currently specify BEFORE or

AFTER onINSERT, DELETE or UPDATE of a tuple as a trigger event.

</para>

<sect1>