problem: native id already in use.

scenario: table a (id,col1,col2,col3) id is identity column in tables a,b
table b(id,col1,col2,a.id) a.id refers to the id column in table a
where: i am performing the persistence in a stateless CMP EJB
sequence: persist table a
persist table b

upon persistence of table a lets day @@identity is 1
upon peristence of table b the @@identity is returing
1. If i have two records going into table b for the first time
record 1 is ok but for the second record i am getting the error.