Question

What general guidelines should I go by when considering whether I should mark a field ‘not null’ as opposed to just declaring everything but the primary key null?

Should ‘not null’ fields have DEFAULT values?

Answer 1

Depends on how you want your application to behave.

• First, there will never ever ever be a possible row where this value does NOT contain meaningful data, then use NOT NULL. That is, this value will always be meaningful and represent something.
• Do you want the value to always be filled out by the user or programmer in some form or fashion? Use NOT NULL without a DEFAULT
• Do you want it to be optional to users and programmers? Use NOT NULL with a DEFAULT