Adding a Unique Index to an IDENTITY Column

For optimum performance, Sybase recommends creating a unique index on the IDENTITY column. For example, to create a unique index named comp_id on the IDENTITY column created above, enter:

create unique index comp_id 
on composers(id)

For more information about creating a unique index, see Chapter 11, “Creating Indexes on Tables,” of the Transact-SQL User’s Guide.