The DROP statement deletes an object. Any objects that are directly or indirectly dependent on that object are either deleted or made inoperative. (See Inoperative Trigger and Inoperative views for details.) Whenever an object is deleted, its description is deleted from the catalog and any packages that reference the object are invalidated.
Invocation
This statement can be embedded in an application program or issued through the use of dynamic SQL statements. It is an executable statement that can be dynamically prepared.
Authorization
The privileges that must be held by the authorization ID of the DROP statement when dropping objects that allow two-part names must include one of the following:
The authorization ID of the DROP statement when dropping a schema must have SYSADM or DBADM authority or be the schema owner as recorded in the OWNER column of SYSCAT.SCHEMATA.
The authorization ID of the DROP statement when dropping a buffer pool, nodegroup, or table space must have SYSADM or SYSCTRL authority.
The authorization ID of the DROP statement when dropping an event monitor must have SYSADM or DBADM authority
Syntax
>>-DROP--------------------------------------------------------->
(1)
>-----+-ALIAS-------alias-name---------------------------------------+>
+-BUFFERPOOL--bufferpool-name----------------------------------+
+-EVENT--MONITOR--event-monitor-name---------------------------+
+-FUNCTION----function-name--+-------------------------------+-+
| '-(-- .-,-----------. | |
| |-------------------+---)--' |
| '----data-type---+--' |
+-SPECIFIC FUNCTION--specific-name-----------------------------+
+-INDEX--index-name--------------------------------------------+
+-NODEGROUP--nodegroup-name------------------------------------+
| (2) |
+-PACKAGE-------package-name-----------------------------------+
+-PROCEDURE--procedure-name--+-------------------------------+-+
| '-(-- .-,-----------. | |
| |-------------------+---)--' |
| '----data-type---+--' |
+-SPECIFIC PROCEDURE--specific-name----------------------------+
+-SCHEMA--schema-name--RESTRICT--------------------------------+
+-TABLE--table-name--------------------------------------------+
+-TABLESPACE--tablespace-name----------------------------------+
+-TRIGGER--trigger-name----------------------------------------+
+-+----------------+---TYPE--type-name-------------------------+
| | (3) | |
| '-DISTINCT-------' |
'-VIEW--view-name----------------------------------------------'
>--------------------------------------------------------------><
Notes:
Description
All tables, views and triggers (75) that reference the alias are made inoperative.
If the identified event monitor is ON, an error (SQLSTATE 55034) is raised. Otherwise, the event monitor is deleted.
If there are event files in the target path of the event monitor when the event monitor is dropped, the event files are not deleted. However, if a new event monitor is created which specifies the same target path, then the event files are deleted.
There are several different ways available to identify the function instance:
If the data-type is unqualified, the type name is resolved by searching the schemas on the SQL path. This also applies to data type names specified for a REFERENCE type.
It is not necessary to specify the length, precision or scale for the parameterized data types. Instead, an empty set of parentheses may be coded to indicate that these attributes are to be ignored when looking for a data type match.
FLOAT() cannot be used (SQLSTATE 42601) since the parameter value indicates different data types (REAL or DOUBLE).
However, if length, precision, or scale is coded, the value must exactly match that specified in the CREATE PROCEDURE statement.
A type of FLOAT(n) does not need to match the defined value for n since 0<n<25 means REAL and 24<n<54 means DOUBLE. Matching occurs based on whether the type is REAL or DOUBLE.
If no function with the specified signature exists in named or implied schema, an error (SQLSTATE 42883) is raised.
It is not possible to drop a function that is in either the SYSIBM schema or the SYSFUN schema (SQLSTATE 42832).
Other objects can be dependent upon a function. All such dependencies must be removed before the function can be dropped, with the exception of packages which are marked inoperative. An attempt to drop a function with such dependencies will result in an error (SQLSTATE 42893). See page *** for a list of these dependencies.
If the function can be dropped, it is dropped.
Any package dependent on the specific function being dropped is marked as inoperative. Such a package is not implicitly rebound. It must either be rebound by use of the BIND or REBIND command or it must be reprepared by use of the PREP command. See the Command Reference for information on these commands.
Packages having a dependency on a dropped index will be invalidated.
Dropping a nodegroup drops all table spaces defined in the nodegroup. All existing database objects with dependencies on the tables in the table spaces (such as packages, referential constraints, etc.) are dropped or invalidated (as appropriate), and dependent views and triggers are made inoperative.
System defined nodegroups cannot be dropped (SQLSTATE 42832).
If a DROP NODEGROUP is issued against a nodegroup that is currently undergoing a data redistribution, the DROP NODEGROUP operation fails an error is returned (SQLSTATE 55038). However, a partially redistributed nodegroup can be dropped. A nodegroup can become partially redistributed if a REDISTRIBUTE NODEGROUP command does not execute to completion. This can happen if it gets interrupted by either an error or a force application all command (76) .
There are several different ways available to identify the procedure instance:
If the data-type is unqualified, the type name is resolved by searching the schemas on the SQL path. This also applies to data type names specified for a REFERENCE type.
It is not necessary to specify the length, precision or scale for the parameterized data types. Instead, an empty set of parentheses may be coded to indicate that these attributes are to be ignored when looking for a data type match.
FLOAT() cannot be used (SQLSTATE 42601) since the parameter value indicates different data types (REAL or DOUBLE).
However, if length, precision, or scale is coded, the value must exactly match that specified in the CREATE FUNCTION statement.
A type of FLOAT(n) does not need to match the defined value for n since 0<n<25 means REAL and 24<n<54 means DOUBLE. Matching occurs based on whether the type is REAL or DOUBLE.
If no procedure with the specified signature exists in named or implied schema, an error (SQLSTATE 42883) is raised.
All indexes, primary keys, foreign keys, and check constraints referencing the table are dropped. All views and triggers (77) that reference the table are made inoperative. All packages depending on any object dropped or marked inoperative will be invalidated. This includes packages dependent on any supertables above the subtable in the hierarchy. Any reference columns for which the dropped table is defined as the scope of the reference become unscoped.
All files that are linked through any DATALINK columns are unlinked. The unlink operation is performed asynchronously so the files may not be immediately available for other operations.
When a subtable is dropped from a table hierarchy, the columns associated with the subtable are no longer accessible although they continue to be considered with respect to limits on the number of columns and size of the row.
The table space will not be dropped (SQLSTATE 55024) if there is any table that stores at least one of its parts in this table space and has one or more of its parts in another table space (these tables would need to be dropped first). System table spaces cannot be dropped (SQLSTATE 42832). A temporary table space can not be dropped (SQLSTATE 55026) if it is the only temporary table space that exists in the database.
Dropping a table space drops all objects defined in the table space. All existing database objects with dependencies on the table space, such as packages, referential constraints, etc. are dropped or invalidated (as appropriate), and dependent views and triggers are made inoperative.
Containers created by the user are not deleted. Any directories in the path of the container name that were created by the database manager on CREATE TABLESPACE will be deleted. All containers that are below the database directory are deleted.
Dropping triggers causes certain packages to be marked invalid. See the "Notes" section in CREATE TRIGGER concerning the creation of triggers (which follows the same rules).
If the user-defined type can be dropped, then for every function, F, that has parameters or a return value of the type being dropped or a reference to the type being dropped, the following DROP FUNCTION statement is effectively executed:
DROP FUNCTION F
It is possible that this statement also would cascade to drop dependent functions. If all of these functions are also in the list to be dropped because of a dependency on the user-defined type, the drop of the user-defined type will succeed (otherwise it fails with SQLSTATE 42893).
The specified view is deleted. The definition of any view or trigger that is directly or indirectly dependent on that view is marked inoperative. Any packages dependent on a view that is dropped or marked inoperative will be invalidated. This includes packages dependent on any superviews above the subview in the hierarchy. Any reference columns for which the dropped view is defined as the scope of the reference become unscoped.
Object Type > Statement v |
A L I A S |
B U F F E R P O O L |
C O N S T R A I N T |
T Y P E |
F U N C T I O N |
I N D E X |
P A C K A G E |
P A R T I T I O N I N G K E Y |
P R I V I L E G E |
P R O C E D U R E |
N O D E G R O U P |
T A B L E |
T A B L E S P A C E |
T R I G G E R |
V l E W |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DROP ALIAS | - | - | - | - | - | - | A3 | - | - | - | - | R3 | - | X3 | X3 |
| DROP BUFFERPOOL | - | - | - | - | - | - | - | - | - | - | - | - | R | - | - |
| ALTER TABLE DROP CONSTRAINT | - | - | C | - | - | - | A1 | - | - | - | - | - | - | - | - |
| DROP FUNCTION | - | - | R | - | R7 | - | X | - | - | - | - | R | - | R | R |
| DROP INDEX | - | - | R | - | - | - | A | - | - | - | - | R19 | - | - | R17 |
| DROP PACKAGE | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| ALTER TABLE DROP PARTITIONING KEY | - | - | - | - | - | - | A1 | - | - | - | - | - | - | - | - |
| REVOKE a privilege10 | - | - | - | - | - | - | A1 | - | - | - | - | X8 | - | X | X8 |
| DROP PROCEDURE | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| DROP NODEGROUP | - | - | - | - | - | - | - | - | - | - | - | - | C | - | - |
| DROP TABLE | - | - | C | - | - | C | A9 | - | - | - | - | RX11 | - | X16 | X16 |
| DROP TABLESPACE | - | - | - | - | - | C6 | - | - | - | - | - | CR6 | - | - | - |
| DROP TRIGGER | - | - | - | - | - | - | A1 | - | - | - | - | - | - | - | - |
| DROP TYPE | - | - | R13 | R4 | C5 | - | A12 | - | - | - | - | R18 | - | R13 | R14 |
| DROP VIEW | - | - | - | - | - | - | A2 | - | - | - | - | - | - | X16 | X15 |
If a package has a statement acting on a typed view, creating or dropping any view in the same view hierarchy will invalidate the package.
Aliases themselves are not dependent on anything. It is possible for an alias to be defined on an object that does not exist.
If a package has a statement acting on a typed table, creating or dropping any table in the same table hierarchy will invalidate the package.
If a package, trigger or view includes the use of OUTER(Z) in the FROM clause, there is a dependency on the SELECT privilege on every subtable or subview of Z. Similarly, if a package, trigger, or view includes the use of DEREF(Y) where Y is a reference type with a target table or view Z, there is a dependency on the SELECT privilege on every subtable or subview of Z.
A subtable is dependent on its supertable up to the root table. A supertable cannot be dropped until all its subtables are dropped.
Notes
Examples
DROP TABLE TDEPT
Example 2: Drop the view VDEPT.
DROP VIEW VDEPT
Example 3: The authorization ID HEDGES attempts to drop an alias.
DROP ALIAS A1
The alias HEDGES.A1 is removed from the catalogs.
Example 4: Hedges attempts to drop an alias, but specifies T1 as the alias-name, where T1 is the name of an existing table (not the name of an alias).
DROP ALIAS T1
This statement fails (SQLSTATE 42809).
Example 5:
Drop the BUSINESS_OPS nodegroup. To drop the nodegroup, the two table spaces (ACCOUNTING and PLANS) in the nodegroup must first be dropped.
DROP TABLESPACE ACCOUNTING DROP TABLESPACE PLANS DROP NODEGROUP BUSINESS_OPS
Example 6: Pellow wants to drop the CENTRE function, which he created in his PELLOW schema, using the signature to identify the function instance to be dropped.
DROP FUNCTION CENTRE (INT,FLOAT)
Example 7: McBride wants to drop the FOCUS92 function, which she created in the PELLOW schema, using the specific name to identify the function instance to be dropped.
DROP SPECIFIC FUNCTION PELLOW.FOCUS92
Example 8: Drop the function ATOMIC_WEIGHT from the CHEM schema, where it is known that there is only one function with that name.
DROP FUNCTION CHEM.ATOMIC_WEIGHT
Example 9: Drop the trigger SALARY_BONUS, which caused employees under a specified condition to receive a bonus to their salary.
DROP TRIGGER SALARY_BONUS
Example 10: Drop the distinct data type named shoesize, if it is not currently in use.
DROP DISTINCT TYPE SHOESIZE
Example 11: Drop the SMITHPAY event monitor.
DROP EVENT MONITOR SMITHPAY
Example 12: Drop the schema from Example 2 under CREATE SCHEMA using RESTRICT. Notice that the table called PART must be dropped first.
DROP TABLE PART DROP SCHEMA INVENTRY RESTRICT
Example 13: Macdonald wants to drop the DESTROY procedure, which he created in the EIGLER schema, using the specific name to identify the procedure instance to be dropped.
DROP SPECIFIC PROCEDURE EIGLER.DESTROY
Example 14: Drop the procedure OSMOSIS from the BIOLOGY schema, where it is known that there is only one procedure with that name.
DROP PROCEDURE BIOLOGY.OSMOSIS
(75) This includes both the table referenced in the ON clause of the CREATE TRIGGER statement and all tables referenced within the triggered SQL statements.
(76) For a partially redistributed nodegroup, the REBALANCE_PMAP_ID in the SYSCAT.NODEGROUPS catalog is not -1.
(77) This includes both the table referenced in the ON clause of the CREATE TRIGGER statement and all tables referenced within the triggered SQL statements.
(78) Not all dependencies are explicitly recorded in the catalog. For example, there is no record of which constraints a package has a dependency on.