Oracle数据库表约束

--新建表BBCREATE TABLE BB(       BID NUMBER(3) PRIMARY KEY,       BNAME VARCHAR2(10));INSERT INTO BB VALUES(1,'JAVA');INSERT INTO BB VALUES(2,'ORACLE');select * from bb;--新建表AACREATE TABLE AA(       AID NUMBER(3),--PRIMARY KEY 主键约束,       ANAME VARCHAR2(20) NOT NULL,--非空约束,       AEMAIL VARCHAR2(20) UNIQUE,--唯一约束       ASEX VARCHAR(20) DEFAULT '男' check(ASEX='男'OR ASEX='女'),--检查约束       ACLAZZID NUMBER(3) --REFERENCES BB(Bid) 外键约束);ALTER TABLE AA ADD CONSTRAINTS FK_AA_ACLAZZID FOREIGN KEY(ACLAZZID) REFERENCES BB(BID);ALTER TABLE AA ADD CONSTRAINTS PK_AA PRIMARY KEY(AID);--新建序列 0开始  自增1 create sequence seq_aa start with 0 increment by 1 minvalue 0;--添加数据INSERT INTO AA VALUES(seq_aa.nextval,'李白','[e-mail]','男',2);INSERT INTO AA VALUES(seq_aa.nextval,'杜甫','[e-mail]','男',2);INSERT INTO AA VALUES(seq_aa.nextval,'白居易','[e-mail]8M','男',2);INSERT INTO AA VALUES(seq_aa.nextval,'王安石','[e-mail]','男',2);--查看数据SELECT * FROM AA;