Check Constraint pomoć?Imam sljedecu tablicu (Oracle):
Code:
CREATE TABLE PROBA
(
ID NUMBER(10),
IME VARCHAR2(20),
PREZIME VARCHAR2(20),
TEST_ID NUMBER(10)
);
CREATE TABLE PROBA
(
ID NUMBER(10),
IME VARCHAR2(20),
PREZIME VARCHAR2(20),
TEST_ID NUMBER(10)
);
Zanima me kako napraviti CONSTRAINT za kolonu TEST_ID,
koja mora biti unique (jedinstvena) ako nije NULL (ovako nekako):
IF (TEST_ID <> NULL)
THEN TEST_ID mora biti UNIQUE
Mozda nesto slicno ovim check constraint-ima:
Code:
ALTER TABLE PROBA ADD
CONSTRAINT TEST_CHK
CHECK (CASE WHEN test_id<>NULL THEN test_id_mora_biti_unique ; END CASE;)
ENABLE
VALIDATE;
ALTER TABLE PROBA ADD
CONSTRAINT TEST_CHK
CHECK (CASE WHEN test_id<>NULL THEN test_id_mora_biti_unique ; END CASE;)
ENABLE
VALIDATE;
Code:
ALTER TABLE proba ADD
CONSTRAINT test_chk
CHECK (CASE WHEN
(SELECT COUNT (test_id)
FROM proba
WHERE test_id <> NULL
HAVING COUNT (test_id) >= 1
)<>0
THEN TRUE END CASE)
ENABLE
VALIDATE;
ALTER TABLE proba ADD
CONSTRAINT test_chk
CHECK (CASE WHEN
(SELECT COUNT (test_id)
FROM proba
WHERE test_id <> NULL
HAVING COUNT (test_id) >= 1
)<>0
THEN TRUE END CASE)
ENABLE
VALIDATE;
HVALAAAAA!
Re: Check Constraint pomoć?
Re: Check Constraint pomoć?