DROP INDEX

Purpose

Use the DROP INDEX statement to remove an index or domain index from the database.

When you drop a global partitioned index, a range-partitioned index, or a hash-partitioned index, all the index partitions are also dropped. If you drop a composite-partitioned index, then all the index partitions and subpartitions are also dropped.

In addition, when you drop a domain index:

• Oracle Database invokes the appropriate routine.

• If any statistics are associated with the domain index, then Oracle Database disassociates the statistics types with the FORCE clause and removes the user-defined statistics collected with the statistics type.

  See Also:

  • Oracle Database Data Cartridge Developer's Guide for information on the routines

  • CREATE INDEX and ALTER INDEX for information on creating and modifying an index

  • The domain_index_clause of CREATE INDEX for more information on domain indexes

  • ASSOCIATE STATISTICS and DISASSOCIATE STATISTICS for more information on statistics type associations

Prerequisites

The index must be in your own schema or you must have the DROP ANY INDEX system privilege.

Syntax

drop_index::=

Description of the illustration drop_index.eps

Semantics

schema

Specify the schema containing the index. If you omit schema, then Oracle Database assumes the index is in your own schema.

index

Specify the name of the index to be dropped. When the index is dropped, all data blocks allocated to the index are returned to the tablespace that contained the index.

ONLINE

Specify ONLINE to indicate that DML operations on the table or partition will be allowed while dropping the index.

FORCE

FORCE applies only to domain indexes. This clause drops the domain index even if the indextype routine invocation returns an error or the index is marked IN PROGRESS. Without FORCE, you cannot drop a domain index if its indextype routine invocation returns an error or the index is marked IN PROGRESS.

Note:

When dropping a domain index with FORCE option, the index will be dropped regardless of any errors happening in the indextype routine. The errors raised by the indextype routine are not reported.

Only use the FORCE option when the index or index partitions are marked IN PROGRESS or when DROP INDEX has already failed.

{ DEFERRED | IMMEDIATE } INVALIDATION

This clause lets you control when the database invalidates dependent cursors while dropping the index. It has the same semantics here as for the ALTER INDEX statement, with the following addition: When you drop an index with DEFERRED INVALIDATION, Oracle database will immediately invalidate any DML statement or query that references the dropped index in its plan.

See { DEFERRED | IMMEDIATE } INVALIDATION in the documentation on ALTER INDEX for the full semantics of this clause.

Restrictions on Dropping Indexes

The following restrictions apply to dropping indexes:

• You cannot drop a domain index if the index or any of its index partitions is marked IN_PROGRESS.

• You cannot specify the ONLINE clause when dropping a domain index, a cluster index, or an index on a queue table.

Examples

Dropping an Index: Example

This statement drops an index named ord_customer_ix_demo, which was created in "Compressing an Index: Example":

DROP INDEX ord_customer_ix_demo;