SQL Check Constraint

Check constraint manage the condition the values enter into record. if the condition evaluates as false, it violates the applied condition.

— CREATE TABLE
CREATE TABLE DATAVALID
(ID INT,NAME VARCHAR2(30)NOT NULL,ADDRESS VARCHAR(33),AGE NUMBER(20) CHECK(AGE>18));

— INSERT RECORDS TO TABLES ex more than 18
INSERT INTO DATAVALID
(ID,NAME,ADDRESS,AGE)VALUES(1,’HARI’,’PARIS’,19);

— INSERTING AGE VALUES LESS THAN 18

— APPLYING TWOCONDITIONS
CREATE TABLE DATAIN
(ID INT PRIMARY KEY,NAME VARCHAR2(30) NOT NULL,ADDRESS VARCHAR2(30)CHECK(ADDRESS=’INDIA’),
CITY VARCHAR2(30)CHECK(CITY=’AGRA’));

— INSERT RECORDS
INSERT INTO DATAIN
(ID,NAME,ADDRESS,CITY)VALUES(1,’PARAM’,’INDIA’,’AGRA’);

— INSERTING ADDRESS AND CITY OTHER THAN INDIA AND AGRA

In simple it apply a condition while inserting values in to tables.