ER, OMT chart of a database

Hi,

e.g.
create table super (name varchar(50));
create table sub (val int4) inherits (super);
create table second (name varchar(50), supernr int4 references
super(oid));

is there any way to get a chart (er, omt), etc. out of a database? I
know that this would be a great programming work but are there any
already fixed solutions? The output does not have to be "graphically" a
kind of textinfo like: "super is a superclass of sub and offers name to
sub" or "table second has a field supernr which is a foreign key of
super" would be okay too.

MArtin