My guess would be that the column has a DefaultValue property of 0, and that
referential integrity is being enforced in the relationship with the
referenced table. As no value of zero will exist in a row in that table,
referential integrity will be violated if the default value is accepted.
You have two alternative solutions. Firstly you can remove the zero
DefaultValue setting (as a rule of thumb a default value is usually
appropriate only if the Required property is True). Secondly you can add a
row to the referenced table with a value of zero in its primary key column,
and something like N/A in a text column (if the key is an autonumber column
you'll need to use an 'append' query to do this; it can't be entered
manually). The first solution is probably appropriate n your case, though
the latter is more relationally pure.
I'm not sure what you mean by "has a afterupdate to automatically enter the
Horse ID". Normally you'd just use a bound combo box, with no need for any
code in its AfterUpdate event procedure. Perhaps you could explain this in
more detail.
Ken Sheridan
Stafford, England
