How to Use NOT NULL Column Constraint Correctly

IN THIS POST, I have explained how to write NOT NULL column “constraint” correctly. Before that, a NULL value means you have not supplied any value or un-known.

NOT NULL is a column constraint. So that user need to enter some value.

Best Example

Create Table Artist
(artist_id int not null,
dob date not null,
salary int);

So the artist table does not allow null values for artist_id and dob. You must enter values.

The salary column is different, where it allows null values when you do not enter any amount.

Table Data of Artist

Summary

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