I've been using mysql for almost 10 years but never even thought about this
commonly seen column definition:
For example, column can be defined like this:
'email_address char(100) NOT NULL DEFAULT NULL'
Can someone exaplain this contradictory statement: how can the column be declared as NOT NULL and at the same type have a default value NULL?
Isnt' NOT NULL mean that value cannot be NULL?
Then how is it possible to have default value as NULL?
I just never thought about it until today, now it's finally time to find the answer.
I hope someone here can explain this really well. Thanks.