Execute permsissions on fuctions

Other SQL servers have the concept of stored procedures having different
permissions.

For instance a procedure that can update a table.

Since a web site typically connects as the webuser (or equiv postgres
user), I do not want to offer update to the webuser.

The way I have done this elsewhere is to create a stored procedure that
could update the table, and allow the webuser to update the table.  The
procedure had perms of a user who could update the table, but the
webuser could not.

How can I do this in Postgres?

Thanks.

-- 
Zot O'Connor

http://www.ZotConsulting.com
http://www.WhiteKnightHackers.com