I do not hink you can do it in a table but in a form.
If DSum <>0 then message and not allow change of checkbox.
--
Build a little, test a little.
"jaworski_m" wrote:
> > You do realize that with this rule enforced at table level, you can only have
> > two records in your table, right? (one Yes and one No).
>
> Yes, correct. But I would like to have Many records (not only 2) and only
> ONE with value "Yes".
>
>
>
> "PieterLinden via AccessMonster.com" wrote:
>
> > jaworski_m wrote:
> > >Hello,
> > >Suppose there's a table (many side):
> > >
> > >ID (PK)
> > >ID_foreign (FK)
> > >field 1
> > >field 2
> > >yes/no field
> > >
> > >How can I allow ONLY ONE record to have "yes/no field" = True? (with table
> > >validation rule)
> > >In case a user sets a second record "yes/no field" = True an error is
> > >triggered.
> > >
> > What happens when you add a unique index (no duplicates) to the yes/no field?
> > You do realize that with this rule enforced at table level, you can only have
> > two records in your table, right? (one Yes and one No).
> > >Thank you for suggestions.
> > >
> > >Access 2003
> >
> > --
> > Message posted via http://www.accessmonster.com
> >
> > .
> >