>Thank you
>
>Could you say something about auto-increment integer field ?
>
>Is it possible on free tables ?

Just a word of caution on AutoInc fields. If you need to save parent and child at the same time, in other words, get autoinc value without first doing tableupdate on the parent, you would not be able to do it. Thus is may be wise to use NextID extra table approach.

In one of my recent applications I used AutoInc fields and then have to overcome certain issues to make it work.