Question

I have a customer file in MS ACCESS, it contains many tables.

Case:

In table(X) for Column(Y) there is validation rule of “=1 Or 2”. I want to change it to “=1 OR 2 OR 3 OR 4” if Possible, Its an Byte column. Otherwsie i want to completly remove the validation rule for that column. I am using C# and i need a query to do so…….

Answer 1

Access SQL can not be used to add, remove, or alter a Validation Rule. That can only be done through the DAO TableDef.

If you were using VBA in Access, you could do this to create your Validation Rule.

CurrentDb.TableDefs("X").Fields("Y").ValidationRule = "IN (1,2,3,4)"

I used IN (1,2,3,4) instead of 1 OR 2 OR 3 OR 4, but either should work.

Perhaps you can use Microsoft.Office.Interop.Access to do the same from c#.

An alternative would be to create a check constraint with Access SQL. A check constraint is not the same as a Validation Rule, but could be used to accomplish the same goal.

ALTER TABLE X ADD CONSTRAINT one_to_four CHECK (Y IN (1,2,3,4));

You would still need to discard the existing Validation Rule. If that’s not feasible, you could create a new table with the same structure as the old, add the check constraint, and finally load data from the old to the new table.