sql - 多列检查约束

Question

我有一张桌子依赖

CREATE TABLE DEPENDANT (DEPENDANT_NM VARCHAR2(15) PRIMARY KEY,
  DEP_GENDER CHAR(1), DEP_BDAT DATE, RELATED_HOW VARCHAR2 (8), ESSNO CHAR(9));
ALTER TABLE DEPENDANT ADD CONSTRAINT FK_ESSNO FOREIGN KEY (ESSNO)
 REFERENCES HW_EMPLOYEE(SSNO);
ALTER TABLE DEPENDANT ADD CONSTRAINT CK_DEP_GENDER CHECK
(DEP_GENDER IN ('M','F'));

我需要添加一个约束，以确保女性家属只能被视为“女儿”或“配偶”，而男性家属只能被视为“儿子”或“配偶”

我是否使用检查约束，例如...

ALTER TABLE DEPENDANT ADD CONSTRAINT CK_RELATEDF CHECK (DEP_GENDER = 'F' AND 
RELATED_HOW IN('Daughter' OR 'Spouse'));

Answer 1

你必须这样写：

ALTER TABLE DEPENDANT 
    ADD CONSTRAINT CK_RELATEDF 
        CHECK (DEP_GENDER = 'F' AND RELATED_HOW IN ('Daughter', 'Spouse'));

编辑：你必须做一次检查：

ALTER TABLE DEPENDANT ADD CONSTRAINT CK_RELATEDF
  CHECK ((DEP_GENDER = 'F' AND RELATED_HOW IN ('Daughter', 'Spouse'))
    OR (DEP_GENDER = 'M' AND RELATED_HOW IN ('Son', 'Spouse')));

Answer 2

“你必须一次性完成”

我对这个断言很感兴趣（不是双关语）。

在我看来，四个约束不仅是可能的而且是可取的（以提供更大的故障消息粒度），例如

ALTER TABLE DEPENDANT ADD CONSTRAINT Gender_legal_values 
    CHECK ( DEP_GENDER IN ( 'M', 'F' ) );

ALTER TABLE DEPENDANT ADD CONSTRAINT Related_legal_values 
    CHECK ( RELATED_HOW IN ( 'Son', 'Daughter', 'Spouse' ) );

ALTER TABLE DEPENDANT ADD CONSTRAINT Female_legal_values
    CHECK ( DEP_GENDER = 'M' OR RELATED_HOW IN ( 'Daughter', 'Spouse' ) );

ALTER TABLE DEPENDANT ADD CONSTRAINT Male_legal_values
    CHECK ( DEP_GENDER = 'F' OR RELATED_HOW IN ( 'Son', 'Spouse' ) );