Removes an index from the current database.
The DROP INDEX statement does not apply to indexes created by defining PRIMARY KEY or UNIQUE constraints (created by using the PRIMARY KEY or UNIQUE options of either the CREATE TABLE or ALTER TABLE statements). For more information about PRIMARY KEY or UNIQUE constraints, see CREATE TABLE (SQL Server Compact).
After DROP INDEX is executed, all the space previously occupied by the index is regained. This space then can be used for any database object.
DROP INDEX cannot be specified on an index on a system table.