제약조건

제약조건 확인

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SELECT owner, constraint_name, constraint_type, table_name
FROM user_constraints;

 

테이블 생성

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CREATE TABLE DEPT
(DEPTNO NUMBER(2) CONSTRAINT PK_DEPT PRIMARY KEY,
ENAME VARCHAR2(14),
LOC VARCHAR2(13) );

 

* 제약조건 생성, 수정, 삭제

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ALTER TABLE emp01 ADD CONSTRAINT PK_EMP01 UNIQUE (empno);
ALTER TABLE emp01 MODIFY CONSTRAINT EMP01_CK CHECK (LOC);

ALTER TABLE emp01 DROP CONSTRAINT PK_EMP01;

ALTER TABLE 테이블 modify 컬럼명 CONSTRAINT 제약조건명 NOT NULL; (NOT NULL일 경우만)

* 외래키 제약조건

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CONSTRAINTS EMP_01_DEPTNO_FK REFERENCES DEPT(DEPTNO)

 

* 체크 제약조건

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CONSTRAINTS EMP_01_DEPTNO_CK CHECK (TITLE IN('사원','대리','과장','부장'))

 

* Defaul 값 제약조건

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indate date default sysdate;