Question

I have supplier table with supplier id as the primary key. I have a supplier type column which can be airline (AL), hotel (HT), Tour (T).

For the supplier type airline (AL) I want the airline_type and airline_abbr columns to be composite unique as well as the airline_type and airline_iata_code to be composite unique.

I don’t want to set this as the primary key because primary key is already declared.

How to go about it? Any ideas or suggestions?

Thanks,

Answer 1

You can create unique filtered indices on your table:

CREATE UNIQUE NONCLUSTERED INDEX IX_Airline_TypeAbbr
ON dbo.Supplier (airline_type, airline_abbr)
WHERE supplier_type = 'AL'

CREATE UNIQUE NONCLUSTERED INDEX IX_Airline_TypeIataCode
ON dbo.Supplier (airline_type, airline_iata_code)
WHERE supplier_type = 'AL'

You can read more about what filtered indexes are and how to use them in Pinal Dave’s excellent blog post on the topic