>I want to change the primary key of a table.
> Can i get the name of the primary key with a select

Yes. Look at table RDB$RELATION_CONSTRAINTS

> and can i use this
> select to drop the primary key ?
> Like "alter table TEST drop constraint (select pk_name from ... where
> table_name like 'TEST')"
> Ist this possible (with FB 2.0) ?

No.

Ivan
http://www.volny.cz/iprenosil/interbase/