Comment by nlitened

From my experience, any new field that gets added to existing tables (after a non-trivial system got deployed to production environment with actual clients) must always be nullable.

Firstly, it’s more practical and brings fewer surprises to all people involved (especially if there are many people involved).

Secondly, if we’re being pedantic, it is a mere acknowledgement of the fact that the field was not there before and things worked without it, and now the field is here, so in all senses the field _is actually_ optional, so all the touching code should know how to handle this.