SQL NOT NULL Constraint

By default, a table column can hold NULL values.

SQL NOT NULL Constraint

The NOT NULL constraint enforces a column to NOT accept NULL values.
The NOT NULL constraint enforces a field to always contain a value. This means that you cannot insert a new record, or update a record without adding a value to this field.
The following SQL enforces the "P_Id" column and the "LastName" column to not accept NULL values:

P_Id int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Address varchar(255),
City varchar(255)

SQL NOT NULL Constraint Reviewed by 1000sourcecodes on 02:54 Rating: 5
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