pgsql-server: Update DELETE FROM: < * Allow DELETE to handle table

Log Message:
-----------
Update DELETE FROM:

< * Allow DELETE to handle table aliases for self-joins
> * Allow an alias to be provided for the target table in UPDATE/DELETE
276,279c276,282
< There is no way to create a table alias for the deleted table for use
< in the DELETE WHERE clause. The agreed approach is to allow a USING
< clause to specify additional tables. UPDATE already has an optional
< FROM clause for this purpose.
> This is not SQL-spec but many DBMSs allow it.
>
> * Allow additional tables to be specified in DELETE for joins
>
> UPDATE already allows this (UPDATE...FROM) but we need similar
> functionality in DELETE. It's been agreed that the keyword should
> be USING, to avoid anything as confusing as DELETE FROM a FROM b.

Modified Files:
--------------
pgsql-server/doc:
TODO (r1.1325 -> r1.1326)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/doc/TODO.diff?r1=1.1325&r2=1.1326)