EllisLab/CodeIgniter — pull request #1133 by SammyK (2012-03-05 23:03:44+00:00)
Title: Fixed bug for PostgreSQL driver where limit() & order_by() throws error

PostgreSQL does not support the "LIMIT" or "ORDER BY" syntax on UPDATE or DELETE queries:

http://www.postgresql.org/docs/8.1/static/sql-update.html
http://www.postgresql.org/docs/8.1/static/sql-delete.html

So I removed it from the Postgres driver. This fix allows frameworks that run both MySQL and Postgres databases to keep the limit() & order_by() functionality for MySQL.