ERA model generator

Hello,
don't somebody know about an application which allows
to create the ERA model of a database using GUI and generate
SQL code which makes this model real?
eg:
GUI: [table1]--[table2]
[table1]
|-attr1
|-attr2
...
SQL code:
create table1 (table1_id datatype,attr1 datatype1,attr2 datatype2...);
...

The perfect candidate:
- is free
- can generate SQL compliant with both PostgreSQL and MySQL
- can be run on Linux (might run on Win*)
- has adjustable SQL code output

Since we don't live in the perfect world I'm ready to compromise...

Thank you in advance.
--
Best regards,
Dusan Juhas