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Ankit Singh

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Posted on    November-03-2015 10:00 PM

 .NET SQL Server 

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what is   NOT NULL Constraint in sql server .

aditya kumar Patel

Total Post:254

Posted on    November-03-2015 10:15 PM

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 "U_Id" column and the "LastName" column to not accept NULL values:



U_Id int NOT NULL,

LastName varchar(255) NOT NULL,

FirstName varchar(255),

Address varchar(255),

City varchar(255)


--when we want insert null value lastname get error

insert into Users(U_Id,LastName,FirstName,Address,City)



When I insert lastname null get error.

Result :

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