Checking referencial integrity

Good day all

I am hoping that someone can perhaps assist in the
following as I don't have as much experience in postgres as most people
on this list.

I need to verify and check the referencial integrity of
a database containing over 700 tables.

In order to do this I have been trying to find a way to
create a visual digram of all the references / dependencies between
tables (foreign keys,etc...) however doing this manually is taking way
too long.

After trying to google for better alternatives, I found
a couple of gui frontends to assist in this, however I have been unable
to find one that works.

Either they merely create reports without graphical
views (like pgdesigner) and crashes whenever you want to do anything
else with it or they do not even want to run on my machine due to
millions of dependencies of library version differences,etc....

This database is but one of many databases I need to
do this for thus manually doint this will be a horrible task.

Does anybody perhaps know whether there is a tool
out there that can be used to reverse engineer the database structures,
references,etc... and then output it into graphical form.

Otherwise, if not, I am looking for a linux (ubuntu)
package that can be used to easily create these type of diagrams.

I would really appreciate the help here as it will
save me lots of time.

Regards
Machiel