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

.