Unless you specify the
PURGE clause, the
TABLE statement does not result in space being released back to the tablespace for use by other objects, and the space continues to count toward the user's space quota.
For an external table, this statement removes only the table metadata in the database. It has no affect on the actual data, which resides outside of the database.
When you drop a table that is part of a cluster, the table is moved to the recycle bin. However, if you subsequently drop the cluster, then the table is purged from the recycle bin and can no longer be recovered with a
Dropping a table invalidates dependent objects and removes object privileges on the table. If you want to re-create the table, then you must regrant object privileges on the table, re-create the indexes, integrity constraints, and triggers for the table, and respecify its storage parameters. Truncating has none of these effects. Therefore, removing rows with the
TRUNCATE statement can be more efficient than dropping and re-creating a table.
The table must be in your own schema or you must have the
TABLE system privilege.
You can perform DDL operations (such as
INDEX) on a temporary table only when no session is bound to it. A session becomes bound to a temporary table by performing an
INSERT operation on the table. A session becomes unbound to the temporary table by issuing a
TRUNCATE statement or at session termination, or, for a transaction-specific temporary table, by issuing a
Specify the schema containing the table. If you omit
schema, then Oracle Database assumes the table is in your own schema.
Specify the name of the table to be dropped. Oracle Database automatically performs the following operations:
All rows from the table are dropped.
All table indexes and domain indexes are dropped, as well as any triggers defined on the table, regardless of who created them or whose schema contains them. If
tableis partitioned, then any corresponding local index partitions are also dropped.
All the storage tables of nested tables and LOBs of
When you drop a range-, hash-, or list-partitioned table, then the database drops all the table partitions. If you drop a composite-partitioned table, then all the partitions and subpartitions are also dropped.
When you drop a partitioned table with the
PURGEkeyword, the statement executes as a series of subtransactions, each of which drops a subset of partitions or subpartitions and their metadata. This division of the drop operation into subtransactions optimizes the processing of internal system resource consumption (for example, the library cache), especially for the dropping of very large partitioned tables. As soon as the first subtransaction commits, the table is marked
UNUSABLE. If any of the subtransactions fails, then the only operation allowed on the table is another
PURGEstatement. Such a statement will resume work from where the previous
TABLEstatement failed, assuming that you have corrected any errors that the previous operation encountered.
You can list the tables marked
UNUSABLEby such a drop operation by querying the
statuscolumn of the
*_OBJECT_TABLESdata dictionary views, as appropriate.
Oracle Database VLDB and Partitioning Guide for more information on dropping partitioned tables.
For an index-organized table, any mapping tables defined on the index-organized table are dropped.
For a domain index, the appropriate drop routines are invoked. Refer to Oracle Database Data Cartridge Developer's Guide for more information on these routines.
If any statistics types are associated with the table, then the database disassociates the statistics types with the
FORCEclause and removes any user-defined statistics collected with the statistics type.
If the table is not part of a cluster, then the database returns all data blocks allocated to the table and its indexes to the tablespaces containing the table and its indexes.
To drop a cluster and all its the tables, use the
CLUSTERstatement with the
TABLESclause to avoid dropping each table individually. See DROP CLUSTER.
If the table is a base table for a view, a container or master table of a materialized view, or if it is referenced in a stored procedure, function, or package, then the database invalidates these dependent objects but does not drop them. You cannot use these objects unless you re-create the table or drop and re-create the objects so that they no longer depend on the table.
If you choose to re-create the table, then it must contain all the columns selected by the subqueries originally used to define the materialized views and all the columns referenced in the stored procedures, functions, or packages. Any users previously granted object privileges on the views, stored procedures, functions, or packages need not be regranted these privileges.
If the table is a master table for a materialized view, then the materialized view can still be queried, but it cannot be refreshed unless the table is re-created so that it contains all the columns selected by the defining query of the materialized view.
If the table has a materialized view log, then the database drops this log and any other direct-path
INSERTrefresh information associated with the table.
Restrictions on Dropping Tables
You cannot directly drop the storage table of a nested table. Instead, you must drop the nested table column using the
You cannot drop the parent table of a reference-partitioned table. You must first drop all reference-partitioned child tables.
You cannot drop a table that uses a flashback data archive for historical tracking. You must first disable the table's use of the flashback data archive.
CONSTRAINTS to drop all referential integrity constraints that refer to primary and unique keys in the dropped table. If you omit this clause, and such referential integrity constraints exist, then the database returns an error and does not drop the table.
PURGE if you want to drop the table and release the space associated with it in a single step. If you specify
PURGE, then the database does not place the table and its dependent objects into the recycle bin.
You cannot roll back a
TABLE statement with the
PURGE clause, nor can you recover the table if you have dropped it with the
Using this clause is equivalent to first dropping the table and then purging it from the recycle bin. This clause lets you save one step in the process. It also provides enhanced security if you want to prevent sensitive material from appearing in the recycle bin.
Oracle Database Administrator's Guide for information on the recycle bin and naming conventions for objects in the recycle bin
Dropping a Table: Example
The following statement drops the
oe.list_customers table created in "List Partitioning Example".
DROP TABLE list_customers PURGE;