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Determines if unique indexes are always created.
SET UNIQUE on | OFF
When SET UNIQUE is ON, the INDEX command always creates the index as if the UNIQUE option is specified. The UNIQUE option has different meanings for different table types. For DBF tables, it allows records with duplicate key values to be stored in the table, but only shows the first record with that key value.
For DB and SQL tables, it prevents records with duplicate key values from being stored in the table; attempting to do so causes a key violation error. This type of index is referred to as a distinct index. You can create the same kind of index for DBF tables by using the DISTINCT option.
Whenever you reindex an index file, dBASE Plus maintains the index in the same way it was created. For more information on unique and distinct indexes, see the INDEX command.