Hi Sergio,

> Hello! Just in case: I use FB2.5

The following refers to Firebird 2.x but 2.5 shouldn't (!) be too different.

> How many space use a null timestamp field in a database?
>
> I'm asking this because I'm thinking in a design that may have about 10 timestamp fields, and in some cases, some of them may be null.
>
> So I don't know if I should use fields, or change the model and use anothe table with one timestamp field and add a record for each event. The events NEVER can be more than 10.

This might help
http://www.firebirdsql.org/file/documentation/reference_material/html/fbint-page-5.html#fbint-p5-examine-data.
Scroll down till you find the section on Nulls and the following one on
Null Status Bitmaps.

They will show that a Null effectively takes very little space at all.
The data are compressed and a bit in the Null status bitmap determines
whether or not that particular field is NULL or not.

Cheers,
Norm.

--
Norman Dunbar
Dunbar IT Consultants Ltd

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