Re: [Firebird-devel] Meaning of RDB$RELATION_FIELDS.RDB$UPDATE_FLAG

[Dmitry Y. <fir...@ya...>]

20.07.2021 14:50, Mark Rotteveel пишет:
> According to the Firebird Language Reference[1], the 
> RDB$RELATION_FIELDS.RDB$UPDATE_FLAG signals whether a column is a 
> computed column (0) or a regular column (1) (or I guess, updatable (1) 
> vs not-updatable (0)).

Updatable vs non-updatable is correct.

> In practice, this doesn't seem to be the case (see 

This should be a bug. Maybe an old one, with wrong RDB$UPDATE_FLAG being 
then preserved through backup-restore.

> https://stackoverflow.com/questions/68451712/finding-computed-fields-in-firebird-2-5 
> and https://github.com/FirebirdSQL/firebird-documentation/issues/157). 
> Helen's Firebird Book lists this column as 'not used by Firebird'.
> 
> So, is this column truly not used by Firebird?

It's set as explained above by Firebird, but the engine does not use 
this information. It's intended for users.


Dmitry