[Technical Issue] Databases - Unique Constraints vs Unique Indexes
Здравейте, каква е разликата между Unique Constraint и Unique Index, в кои случаи е добре да се ползва едното и в кои другото.
От източника... горе-долу...
https://technet.microsoft.com/en-us/library/aa224827(v=sql.80).aspx
"The short answer is that a unique index is just an index, whereas a unique constraint is a unique index that's listed as a constraint object in the database. In the sysobjects table, the unique constraint will have an xtype value of "UQ." But does a unique constraint have any additional behavior that a unique index doesn't have—or vice versa? The answer to that question, it turns out, takes a big of digging."