Looking for tool for Graphic Database Design

Hi All

I am looking for a Graphic Database Design Tool, somewhat like MS Access
that can allow me to define tables, fields and relationships. Also
things like triggers etc, if possible. Something that can interface with
Dia or other similar open source diagramming/ ER tools, though I dont
know of any other.

The tools should preferably able to genearte ddl for postgreSQL. I run
pgSQL 7.4 on RH9.

With regards.
Sanjay.