The NOT NULL constraint enforces a field or column to not contain a null value.
Example of NOT NULL constraint with CREATE TABLE statement:
CREATE TABLE PERSONS ( P_ ID INT NOT NULL, NAME VARCHAR (20) NOT NULL, AGE INT, PRIMARY KEY (P_ID) );
Example of NOT NULL constraint with ALTER TABLE statement:
ALTER TABLE PERSONS MODIFY AGE INT NOT NULL;
One reply on “Not Null Constraint in SQL”
Constraints in SQL - Scaz January 26, 2023 at 5:14 pm
[…] 3. SQL NOT NULL Constraint. […]