The following sequence of commands will create the table test_table with OID 420, having three columns oid, cola and colb of type oid, int4 and text, respectively, and insert two rows into the table:

create test_table 420 (oid = oid, cola = int4, colb = text)
open test_table
insert ( 421 1 'value 1' )
insert ( 422 2 _null_ )
close test_table