What is a NOT NULL constraint ?

[chinmay.sahoo]

A not null constraint enforces that the column will not accept null values. Not null constraints are used to enforce domain integrity

 

[PariJain]

The NOT NULL constraint enforces a column to NOT accept NULL values. The NOT NULL constraint enforces a field to always contain a value.

 

[Vinodji]

These are the column which did not accept Null values.

 

[Jalaj]

It is that box which you do not leave without entering the text.

 

[EminenceEvent]

Not null is used to make a field/column fill necessary.

 

[fix.97]

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.

 

[zozoreview]

The not-null constraint is a restriction placed on a column in a relational database table. It enforces the condition that, in that column, every row of data must contain a value - it cannot be left blank during insert or update operations. If this column is left blank, this will produce an error message and the entire insert or update operation will fail.