定义两个字段的check约束.txt

SQL语言常用的一些命令各代码

/*一个条件*/

CREATE TABLE P1
( 
 PNO NUMERIC NOT NULL,

 PNAME TEXT NOT NULL, 

 COLOR CHAR(2) NOT NULL, 

 WEIGHT INT
)




alter table P1 add CONSTRAINT  C4 CHECK(WEIGHT<case when COLOR ='红' then 50 end)




/*两个条件*/
color='红'时，weight<50并且pno=2n+1(奇数)

CREATE TABLE P1

( 
 PNO int NOT NULL,

 PNAME TEXT NOT NULL, 

 COLOR CHAR(2) NOT NULL, 

 WEIGHT INT,
 
constraint c4
check(weight<case when color='红'then 50 end and  pno%2=case when color='红' then 1 end)
)