To delete an index for a relation, you need the Oracle Rdb DELETE
    privilege to the relation.

    You cannot delete an index definition if there is a storage map
    that specifies the index in a PLACEMENT VIA clause.

    You must execute this statement in a read/write transaction.
    If there is no active transaction and you issue this statement,
    Oracle Rdb starts a read/write transaction implicitly.

    Other users are allowed to be attached to the database when you
    issue the DELETE INDEX statement.