db2设置联合主键
create table table_a (
ID_A VARCHAR(255) not null ,
ID_B VARCHAR(32) not null,
FOREIGN KEY (ID_A) REFERENCES Table_B (ID_A)
);

alter table table_a add constraint PK_FA PRIMARY KEY (ID_A , ID_B );

创建表a，外键为表b的主键，增加联合主键