ger11sktipt

CREATE TABLE empl (
    name VARCHAR2(64),
    ssn NUMBER(1,0) primary key
);
CREATE TABLE depen (
    name VARCHAR2(64),
    gender NUMBER(1,0),
    essn NUMBER(1,0),
    constraint depen_essnname_pk PRIMARY KEY(essn, name),
    constraint depen_essn_fk foreign key (essn) references empl (ssn)
);
--
INSERT INTO empl VALUES ('klaus', 1);
INSERT INTO empl VALUES ('heidi', 2);
INSERT INTO empl VALUES ('hans', 3);
--
INSERT INTO depen VALUES ('hans', 1, 1);
INSERT INTO depen VALUES ('werner', 2, 1);
INSERT INTO depen VALUES ('chihiro', 1, 3);
INSERT INTO depen VALUES ('hinazuki', 2, 2);
DELETE FROM depen WHERE EXISTS (SELECT * FROM depen );
COMMIT;
SELECT * FROM depen;
INSERT INTO depen VALUES ('hans', 1, 1);
INSERT INTO depen VALUES ('werner', 2, 1);
INSERT INTO depen VALUES ('chihiro', 1, 3);
SELECT * FROM depen;
COMMIT;
INSERT INTO depen
    SELECT * FROM depen;
INSERT INTO depen VALUES ('hinazuki', 2, 2);
SELECT * FROM depen;
SELECT COUNT(*) FROM depen;
ROLLBACK;
ROLLBACK;
SELECT COUNT(*) FROM depen;