Prevents multiple records with the same expression value from being included in the index. Includes only the first record for each value.
Restricts the row included in the index to those with unique key values. If two or more rows have the same key value, only the first row with the key value is included. The "first" row is determined by row number (the order in which you entered rows). This field does not apply to secondary indexes on Paradox tables. A primary index in a Paradox table requires keys to be unique.