[INIMSS] How to foreign key

Hi

Is there any way that I can manage the relation between two tables in some 
what automatic way?

I have two tables A and B with primary keys pka and pkb respectively, of type 
serial. the pka is refered in the table B as foreign key. Its somewhat like 
the one given below.
   Table A
-------------
pka    | serial
name    | varchar(20)
status    | int4
   Table B
-------------
pka    | serial
pkb    | int4
child    | varchar(20)
status    | int4

Now the operator enters information to both the table from the same GUI 
window, so that the data relevant to table A is inserted and we take the 
newly got pka value by selecting ths MAX(A.pka). Then we insert the data 
relevant to the table B along with the new pka value. Here both the tables 
are exclusively locked before starting the data insertions, and later 
unlocked.

This was the method I used in my program. Is there any other method by which 
we can make it in a better way?

Thanks
Dino Cherian K