① PRIMARY KEY constraint Pk_name primary key <column_name>
② FOREIGN KEY constraint fk_name foreign key (COLUMN_NAME) reference table_name (COLUMN_NAME)
③ checking constraint ck_name check (condition)
④ Unique constraint un_name unique (column_name)
⑤ non-empty <column name> <data type> not NULL,
⑥ Default value <column name> <data type> default <default value> --Creating the Train table Create table T_train (Trainnum VARCHAR2 () primary key, Startstation VARCHAR2 (+), Endstation VARCHAR2 (5 0), STARTTIME VARCHAR2 (+), ENDTIME VARCHAR2 (a), TotalTime VARCHAR2 (+), TYPE VARCHAR2 (+), OBJ VARCHAR2 (100))--Create TABLE T_station (Trainnum VARCHAR2 (50),--Train number Startstation VARCHAR2 (50),--Initial account Taiwan endstation VARCHAR2 (50),--End station STARTTIME VARCHAR2 (50),--Start time ENDTIME VARCHAR2 (50),--End time TotalTime VA RCHAR2 (50),--Total time Price FLOAT,--Prices OBJ VARCHAR2 (100),--remark constraint fk_trainnum foreign key (Trainn UM) references T_train (trainnum)--constraint foreign key-associated train table--Create TABLE T_seat (Trainnum VARCHAR2 (+), Seattype VARCHAR2 (50), Seatno VARCHAR2 (), Seatprice FLOAT, Seatstatu INTEGER, OBJ VARCHAR2 (+), constraint T_fk_trainnum Foreign KEY (Trainnum) references T_train (trainnum)--constraint foreign key-associated train table--Create Order Form table T_order (Onumber VARCHAR2 (50) Primary KEY, Trainnum VARCHAR2, STARTTIME VARCHAR2, ENDTIME VARCHAR2 (+), price FLOAT, Seatno VARCHAR2 (+), SEA Ttype VARCHAR2, USERNAME VARCHAR2 (), PhoneNumber VARCHAR2 (+), Idcard VARCHAR2 (e), EMAIL Varch AR2 (+), OBJ VARCHAR2 (+), constraint O_fk_trainnum foreign key (trainnum) references T_train (trainnum)--Constraint foreign key -Associated train table-) CREATE TABLE T_userinfo (USERNAME VARCHAR2, ADDRESS VARCHAR2 (+), EMAIL VARCHAR2 (+), PHONE Number VARCHAR2 (+), Idcard VARCHAR2 (+), OBJ VARCHAR2 (100))--Train offer CREATE TABLE t_favorable (Trainnum varch AR2 (,--) train number STARTTIME VARCHAR2 (50),--Start time ENDTIME VARCHAR2 (50),--end time discount float,--discount price float ,--Discounted price OBJ VARCHAR2 (+),--remarks constraint F_fk_trainnum foreign key (trainnum) references T_train (trainnum)- -Constraint foreign key-associated train table-)
Database creation Common constraints and case references
