Prevent duplicate records for calculated field

[LoveLEE143]

I have a table for storing vehicles. The table contains the following fields:
VehicleID
Make


Model
Trim
Build Date Begin
Build Date End
Vehicle Name - a concatenation of 'Make' 'Model' 'Trim' 'Build Date Begin' and 'Build Date End'

The 'Vehicle ID' is the primary key, the rest of the fields can't be indexed with no duplicates. Is there a way of preventing one from saving a duplicate VehicleName on the table since it is a calculated field.

[orange]

You should NOT do what you are trying to do with that PK set up.
You will have partial dependencies by design.

Use an autonumber PK for Access, if you want to output a concatenated field value of
'Make' 'Model' 'Trim' 'Build Date Begin' and 'Build Date End' then go for it. But do NOT make that concatenation the primary key.

[LoveLEE143]

You should NOT do what you are trying to do with that PK set up.
You will have partial dependencies by design.

Use an autonumber PK for Access, if you want to output a concatenated field value of
'Make' 'Model' 'Trim' 'Build Date Begin' and 'Build Date End' then go for it. But do NOT make that concatenation the primary key.

The vehicleID is the PK which is a auto number. But I need to prevent duplicate results of the concatenation.

[orange]

Sorry for reading the PK as I did --???? For some reason, I got the message you were using the concatenation as PK. When I read it now, I see I misread/misunderstood/ (was thinking of something else)???


You can make a multifield (compound) unique index.
I would not save an individual field as Vehicle name.
I would use an autonumber PK - if that's what you're using for VehicleID - OK.

Then, you can make a compound unique index on the combination of fields you suggest. see this for more info

Is it possible to have more than 1 vehicle with same
'Make' and 'Model' and 'Trim' and 'Build Date Begin' and 'Build Date End'? If it is, then you know you will have physical duplicates so this would be a non-starter.

If any of these fields could be NULL that would also make this a non-starter.