Null vs Not Null

[sergeidave]

Hi guys,

 

If I create a field in a table as a "Not Null" would this prevent a new record to be created unless that field is properly filled?

I'm playing around with a test website and I tried leaving blank a "Not null" field but the record was created anyway with that field empty.

Maybe I'm not understanding the Null vs Notnull stuff correctly?

If so, how would one restrict the creation of new records unless a not null field contains valid (or data at all) data?

Thanks!!

[Yesideez]

Let's say you have a numeric field.

 

You won't be able to insert nothing into the field (as it must be a number) so setting the field to NULL allows you to enter NULL instead.

INSERT INTO table (`age`) VALUES (NULL)