数据库创表常用约束以及案例参照

②外键 constraint fk_name foreign key(column_name) reference table_name(column_name)
③检查 constraint ck_name check (condition)
④唯一 constraint un_name unique (column_name)
⑤非空 <column name> <data type> not null,
⑥默认值<column name> <data type> default <default value>, --创建火车表 create table T_TRAIN ( TRAINNUM VARCHAR2(50) primary key, STARTSTATION VARCHAR2(50), ENDSTATION VARCHAR2(50), STARTTIME VARCHAR2(50), ENDTIME VARCHAR2(50), TOTALTIME VARCHAR2(50), TYPE VARCHAR2(20), OBJ VARCHAR2(100) ) --创建占台表 create table T_STATION ( TRAINNUM VARCHAR2(50), --火车编号 STARTSTATION VARCHAR2(50), --初始占台 ENDSTATION VARCHAR2(50), --结束站 STARTTIME VARCHAR2(50), --开始时间 ENDTIME VARCHAR2(50), --结束时间 TOTALTIME VARCHAR2(50), --总的时长 PRICE FLOAT, --价格 OBJ VARCHAR2(100), --备注 constraint fk_TRAINNUM foreign key (TRAINNUM) references T_TRAIN(TRAINNUM) --约束外键-关联火车表 - ) create table T_SEAT ( TRAINNUM VARCHAR2(50), SEATTYPE VARCHAR2(50), SEATNO VARCHAR2(50), SEATPRICE FLOAT, SEATSTATU INTEGER, OBJ VARCHAR2(100), constraint t_fk_TRAINNUM foreign key (TRAINNUM) references T_TRAIN(TRAINNUM) --约束外键-关联火车表 - ) --创建订单表 create table T_ORDER ( ONUMBER VARCHAR2(50) primary key, TRAINNUM VARCHAR2(50), STARTTIME VARCHAR2(50), ENDTIME VARCHAR2(50), PRICE FLOAT, SEATNO VARCHAR2(50), SEATTYPE VARCHAR2(20), USERNAME VARCHAR2(50), PHONENUMBER VARCHAR2(30), IDCARD VARCHAR2(50), EMAIL VARCHAR2(50), OBJ VARCHAR2(100), constraint o_fk_TRAINNUM foreign key (TRAINNUM) references T_TRAIN(TRAINNUM) --约束外键-关联火车表 - ) create table T_USERINFO ( USERNAME VARCHAR2(50), ADDRESS VARCHAR2(100), EMAIL VARCHAR2(50), PHONENUMBER VARCHAR2(30), IDCARD VARCHAR2(50), OBJ VARCHAR2(100) ) --火车优惠 create table t_favorable ( TRAINNUM VARCHAR2(50),--火车编号 STARTTIME VARCHAR2(50), --开始时间 ENDTIME VARCHAR2(50), --结束时间 discount float, --优惠折扣 price float, --优惠价格 OBJ VARCHAR2(100),--备注 constraint f_fk_TRAINNUM foreign key (TRAINNUM) references T_TRAIN(TRAINNUM) --约束外键-关联火车表 - )

数据库创表常用约束以及案例参照

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