Query to return schema/table/columname/columntype

Hi all,

I am trying to modify the dabo (a python wxpython
ide for database forms creation) code to allow the
selection of tables in any schema. I need a query
that will return records with schema, table,
columname and columne type.

For background I am selecting table & schema by
the query:
SELECT schemaname || '.' || tablename AS tablename
FROM pg_tables ORDER BY tablename;

Then I need to obtain the columns within that
table/schema. The original query was:
select c.oid,a.attname, t.typname
from pg_class c inner join pg_attribute a on
a.attrelid = c.oid inner join pg_type t on
a.atttypid = t.oid where c.relname = 'thetablename
and a.attnum > 0;

Now my problem is how to create a new column to
replace c.relname so I can query on
"theschemaname.thetablename".

Any suggestions will be welcomed. Thanks,

Phil