Re: [Firebird-devel] Adding NOT NULL fields with DEFAULT

[Rustam G. <fir...@ma...>]

Alexander Peshkoff > But what should be firebird's behavior if you've forgotten to perform that update?

It can and must  be discussed. Begining for discussion i already
mentioned above - "bring an exception if there are wrong data".

Alexander Peshkoff > Is destroying database possible in such case to teach user to always 
> perform such update?

I think, any cases is better than getting difference results (values) from
the same record under difference environment (user, transaction etc).
Where is and how db must be destroyed - i can't see here. Can you
give some example ?

Alexander Peshkoff > Something similiar happens when you try to restore a 
> copy of such database - copy is not restorable

Yes. That's why this must be exceptioned.

Alexander Peshkoff > which sometimes is a kind of destroyed database.

Why you equals unrestorable backup and destroyed original db ?

Alexander Peshkoff > As for me I dislike such behavior:))

Me too. :) See above about checking data when changing DDL.
May be optional, may be another way - but it must be simple and
transparent way (for understanding and using by end users).

> BTW, if it's documented that providing default value makes it work like you 
> did perform that update with default value, you get exactly same behavior, 
> but no need to waste time for that mass update, also avoiding a lot of 
> garbage in your database when the table is big.

I vote against behaviour like "calc value when read". Getting/calcing
value when changing DDL (with using default value too) - good, using
some syntax like "add not null <expression>" - good, etc.

WBR, GR