The UNIQUE keyword causes the SAS System to reject any change to a table that would cause more than one row to have the same index value. Unique indexes guarantee that data in one column, or in a ...

Duplicate and Ignore on MySQL Inserts. MySQL table primary keys and unique indexes prevent multiple rows with the same index from being added to the table. If you try to insert a duplicate row ...

Using table indexes in databases enables you to find information within the database faster and more efficiently than not using table indexes. The two index types that are commonly used in ...