|Oracle8i SQL Reference
Release 3 (8.1.7)
Part Number A85397-01
DROP SEQUENCE to UPDATE, 15 of 27
TABLE statement to lock one or more tables (or table partitions or subpartitions) in a specified mode. This lock manually overrides automatic locking and permits or denies access to a table or view by other users for the duration of your operation.
Some forms of locks can be placed on the same table at the same time. Other locks allow only one lock per table.
A locked table remains locked until you either commit your transaction or roll it back, either entirely or to a savepoint before you locked the table.
A lock never prevents other users from querying the table. A query never places a lock on a table. Readers never block writers and writers never block readers.
The table or view must be in your own schema or you must have the
TABLE system privilege, or you must have any object privilege on the table or view.
Specify the schema containing the table or view. If you omit
schema, Oracle assumes the table or view is in your own schema.
Specify the name of the table to be locked. If you specify
view, Oracle locks the view's base tables.
If you specify
subpartition), Oracle first acquires an implicit lock on the table. The table lock is the same as the lock you specify for
subpartition, with two exceptions:
SHARElock for the subpartition, Oracle acquires an implicit
SHARElock on the table.
EXCLUSIVElock for the subpartition, Oracle acquires an implicit
EXCLUSIVElock on the table.
If you specify
table is composite-partitioned, then Oracle acquires locks on all the subpartitions of
Specify a database link to a remote Oracle database where the table or view is located. You can lock tables and views on a remote database only if you are using Oracle's distributed functionality. All tables locked by a
TABLE statement must be on the same database.
If you omit
dblink, Oracle assumes the table or view is on the local database.
See Also: "Referring to Objects in Remote Databases" for information on specifying database links
Specify one of the following modes:
SHAREallows concurrent access to the locked table, but prohibits users from locking the entire table for exclusive access.
SHAREis synonymous with
UPDATE, which is included for compatibility with earlier versions of Oracle.
EXCLUSIVEis the same as
SHARE, but also prohibits locking in
SHAREmode. Row Exclusive locks are automatically obtained when updating, inserting, or deleting.
SHAREallows concurrent queries but prohibits updates to the locked table.
EXCLUSIVEis used to look at a whole table and to allow others to look at rows in the table but to prohibit others from locking the table in
SHAREmode or updating rows.
EXCLUSIVEallows queries on the locked table but prohibits any other activity on it.
Specify NOWAIT if you want Oracle to return control to you immediately if the specified table (or specified partition or subpartition) is already locked by another user. In this case, Oracle returns a message indicating that the table, partition, or subpartition is already locked by another user.
If you omit this clause, Oracle waits until the table is available, locks it, and returns control to you.
The following statement locks the
emp table in exclusive mode, but does not wait if another user already has locked the table:
The following statement locks the remote
accounts table that is accessible through the database link