The
DECLARE GLOBAL TEMPORARY TABLE statement defines a temporary table
for the current session.
The declared temporary table description does not appear
in the system catalog. It is not persistent and cannot be shared with
other sessions. Each session that defines a declared global temporary
table of the same name has its own unique description of the temporary
table. When the session terminates, the rows of the table are deleted,
and the description of the temporary table is dropped.
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 held by the
authorization ID of the statement must include at least one of the
following authorities:
- USE privilege on the USER TEMPORARY table space
- DBADM authority
- SYSADM authority
- SYSCTRL authority
When defining a table using LIKE or a fullselect, the privileges
held by the authorization ID of the statement must also include at
least one of the following authorities on each identified table or
view:
- SELECT privilege on the table or view
- CONTROL privilege on the table or view
- DATAACCESS authority
Syntax
>>-DECLARE GLOBAL TEMPORARY TABLE--table-name------------------->
.-,---------------------.
V |
>--+-(----| column-definition |-+--)--------------------------+-->
+-LIKE--+-table-name1-+--+------------------+--------------+
| '-view-name---' '-| copy-options |-' |
'-AS--(--fullselect--)--WITH NO DATA--+------------------+-'
'-| copy-options |-'
.-ON COMMIT DELETE ROWS---.
>--●--+-------------------------+--●---------------------------->
'-ON COMMIT PRESERVE ROWS-'
.-LOGGED------------------------------------.
>--+-------------------------------------------+--●------------->
| .-ON ROLLBACK DELETE ROWS---. |
'-NOT LOGGED--+---------------------------+-'
'-ON ROLLBACK PRESERVE ROWS-'
>--●--+--------------+--+---------------------+----------------->
'-WITH REPLACE-' '-IN--tablespace-name-'
>--●--+-------------------------+--●---------------------------><
'-| distribution-clause |-'
column-definition
|--column-name--| data-type |--+--------------------+-----------|
'-| column-options |-'
data-type
|----| built-in-type |------------------------------------------|
built-in-type
|--+-+-SMALLINT----+------------------------------------------------------------------------+--|
| +-+-INTEGER-+-+ |
| | '-INT-----' | |
| '-BIGINT------' |
| .-(5,0)-------------------. |
+-+-+-DECIMAL-+-+--+-------------------------+-------------------------------------------+
| | '-DEC-----' | | .-,0-------. | |
| '-+-NUMERIC-+-' '-(integer-+----------+-)-' |
| '-NUM-----' '-,integer-' |
| .-(53)------. |
+-+-FLOAT--+-----------+--+--------------------------------------------------------------+
| | '-(integer)-' | |
| +-REAL------------------+ |
| | .-PRECISION-. | |
| '-DOUBLE--+-----------+-' |
| .-(34)-. |
+-DECFLOAT--+------+---------------------------------------------------------------------+
| '-(16)-' |
| .-(1)------------------------. |
+-+-+-+-CHARACTER-+--+----------------------------+----------+--+--------------------+-+-+
| | | '-CHAR------' '-(integer-+-------------+-)-' | | (1) | | |
| | | +-OCTETS------+ | '-------FOR BIT DATA-' | |
| | | '-CODEUNITS32-' | | |
| | '-+-VARCHAR----------------+--(integer-+-------------+-)-' | |
| | '-+-CHARACTER-+--VARYING-' +-OCTETS------+ | |
| | '-CHAR------' '-CODEUNITS32-' | |
| | .-(1M)-----------------------------. | |
| '-+-CLOB------------------------+--+----------------------------------+--------------' |
| '-+-CHARACTER-+--LARGE OBJECT-' '-(integer-+---+-+-------------+-)-' |
| '-CHAR------' +-K-+ +-OCTETS------+ |
| +-M-+ '-CODEUNITS32-' |
| '-G-' |
| .-(1)------------------------. |
+-+-GRAPHIC--+----------------------------+------+---------------------------------------+
| | '-(integer-+-------------+-)-' | |
| | +-CODEUNITS16-+ | |
| | '-CODEUNITS32-' | |
| +-VARGRAPHIC--(integer-+-------------+-)-------+ |
| | +-CODEUNITS16-+ | |
| | '-CODEUNITS32-' | |
| | .-(1M)-----------------------------. | |
| '-DBCLOB--+----------------------------------+-' |
| '-(integer-+---+-+-------------+-)-' |
| +-K-+ +-CODEUNITS16-+ |
| +-M-+ '-CODEUNITS32-' |
| '-G-' |
| .-(1)-------. |
+-+-+-+-NCHAR-------------------+--+-----------+------+-------+--------------------------+
| | | '-NATIONAL--+-CHAR------+-' '-(integer)-' | | |
| | | '-CHARACTER-' | | |
| | '-+-NVARCHAR-------------------------+--(integer)-' | |
| | +-NCHAR VARYING--------------------+ | |
| | '-NATIONAL--+-CHAR------+--VARYING-' | |
| | '-CHARACTER-' | |
| | .-(1M)-------------. | |
| '-+-NCLOB---------------------------+--+------------------+-' |
| +-NCHAR LARGE OBJECT--------------+ '-(integer-+---+-)-' |
| '-NATIONAL CHARACTER LARGE OBJECT-' +-K-+ |
| +-M-+ |
| '-G-' |
| .-(1M)-------------. |
+-+-BLOB----------------+--+------------------+------------------------------------------+
| '-BINARY LARGE OBJECT-' '-(integer-+---+-)-' |
| +-K-+ |
| +-M-+ |
| '-G-' |
+-+-DATE-------------------------+-------------------------------------------------------+
| +-TIME-------------------------+ |
| | .-(--6--)-------. | |
| '-TIMESTAMP--+---------------+-' |
| '-(--integer--)-' |
'---XML----------------------------------------------------------------------------------'
column-options
|--●--+----------+--●--+-------------------------------------------------------------------+--●--|
'-NOT NULL-' +-| default-clause |------------------------------------------------+
'-GENERATED--+-ALWAYS-----+--AS--IDENTITY--+----------------------+-'
'-BY DEFAULT-' '-| identity-options |-'
default-clause
.-WITH-.
|--+------+--DEFAULT--+--------------------+--------------------|
'-| default-values |-'
default-values
|--+-constant-------------------------------------------+-------|
+-datetime-special-register--------------------------+
+-user-special-register------------------------------+
+-CURRENT SCHEMA-------------------------------------+
+-NULL-----------------------------------------------+
+-cast-function--(--+-constant------------------+--)-+
| +-datetime-special-register-+ |
| +-user-special-register-----+ |
| '-CURRENT SCHEMA------------' |
+-EMPTY_CLOB()---------------------------------------+
+-EMPTY_DBCLOB()-------------------------------------+
+-EMPTY_NCLOB()--------------------------------------+
'-EMPTY_BLOB()---------------------------------------'
copy-options
.-COLUMN ATTRIBUTES-.
.-EXCLUDING IDENTITY--+-------------------+-.
|--●--+-------------------------------------+--●--+-------------------------------------------+--●--|
| .-COLUMN-. | | .-COLUMN ATTRIBUTES-. |
'-+-INCLUDING-+--+--------+--DEFAULTS-' '-INCLUDING IDENTITY--+-------------------+-'
'-EXCLUDING-'
distribution-clause
.-,-----------.
.-HASH-. V |
|--DISTRIBUTE BY--+------+--(----column-name-+--)---------------|
Notes:
- The FOR BIT DATA clause can be specified in any order with
the other column constraints that follow. The
FOR BIT DATA clause cannot be specified with string units CODEUNITS32
(SQLSTATE 42613).
Description
- table-name
- Names the temporary table. The qualifier, if specified explicitly,
must be SESSION, otherwise an error is returned (SQLSTATE 428EK).
If the qualifier is not specified, SESSION is implicitly assigned.
Each
session that defines a declared temporary table with the same table-name has
its own unique description of that declared temporary table. The
WITH REPLACE clause must be specified if table-name identifies
a declared temporary table that already exists in the session (SQLSTATE
42710).
It is possible that a table, view, alias, or nickname
already exists in the catalog, with the same name and the schema
name SESSION. In this case:
- A declared temporary table table-name may
still be defined without any error or warning
- Any references to SESSION.table-name will
resolve to the declared temporary table rather than the SESSION.table-name already
defined in the catalog.
- column-definition
- Defines the attributes of a column of the temporary table.
- column-name
- Names a column of the table. The name cannot be qualified, and
the same name cannot be used for more than one column of the table
(SQLSTATE 42711).
A table may have the following attributes:
- A 4K page size with a maximum of 500 columns, where the byte counts
of the columns must not be greater than 4 005.
- An 8K page size with a maximum of 1 012 columns, where the
byte counts of the columns must not be greater than 8 101.
- A 16K page size with a maximum of 1 012 columns, where the
byte counts of the columns must not be greater than 16 293.
- A 32K page size with a maximum of 1 012 columns, where the
byte counts of the columns must not be greater than 32 677.
A
created temporary table cannot have a row-begin column, row-end column,
or a transaction-start-ID column.
For
more details, see "Row Size" in CREATE TABLE statement.
- data-type
- Specifies the data type of the column
- built-in-type
- Specifies a built-in data type. See "CREATE TABLE" for a
description of built-in-type.
A SYSPROC.DB2SECURITYLABEL data type cannot be specified
for a declared temporary table.
- column-options
- Defines additional options related to the columns of the table.
- NOT NULL
- Prevents
the column from containing null values. For specification of null
values, see NOT NULL in CREATE TABLE statement.
- default-clause
- Specifies a default value for the column.
- WITH
- An optional keyword.
- DEFAULT
- Provides a default value in the event a value is not supplied
on INSERT or is specified as DEFAULT on INSERT or UPDATE. If a default
value is not specified following the DEFAULT keyword, the default
value depends on the data type of the column as shown in "ALTER
TABLE".
If the column is based on a column of a typed table, a specific
default value must be specified when defining a default. A default
value cannot be specified for the object identifier column of a typed
table (SQLSTATE 42997).
If a column is defined using a distinct
type, then the default value of the column is the default value of
the source data type cast to the distinct type.
If a column
is defined using a structured type, the default-clause cannot
be specified (SQLSTATE 42842).
Omission of DEFAULT from a column-definition results
in the use of the null value as the default for the column. If such
a column is defined NOT NULL, then the column does not have a valid
default.
- default-values
- Specific types of default values that can be specified are as
follows.
- constant
- Specifies the constant as the default value for the column. The
specified constant must:
- represent a value that could be assigned to the column in accordance
with the rules of assignment
- not be a floating-point constant unless the column is defined
with a floating-point data type
- be a numeric constant or a decimal floating-point special value
if the data type of the column is a decimal floating-point. Floating-point
constants are first interpreted as DOUBLE and then converted to decimal
floating-point if the target column is DECFLOAT. For DECFLOAT(16)
columns, decimal constants having precision greater than 16 digits
will be rounded using the rounding modes specified by the CURRENT
DECFLOAT ROUNDING MODE special register.
- not have nonzero digits beyond the scale of the column data type
if the constant is a decimal constant (for example, 1.234 cannot be
the default for a DECIMAL(5,2) column)
- be expressed with no more than 254 bytes including the quote characters,
any introducer character such as the X for a hexadecimal constant,
and characters from the fully qualified function name and parentheses
when the constant is the argument of a cast-function
- datetime-special-register
- Specifies the value of the datetime special register (CURRENT
DATE, CURRENT TIME, or CURRENT TIMESTAMP) at the time of INSERT, UPDATE,
or LOAD as the default for the column. The data type of the column
must be the data type that corresponds to the special register specified
(for example, data type must be DATE when CURRENT DATE is specified).
- user-special-register
- Specifies the value of the user special register (CURRENT USER,
SESSION_USER, SYSTEM_USER) at the time of INSERT, UPDATE, or LOAD
as the default for the column. The data type of the column must be
a character string with a length not less than the length attribute
of a user special register. Note that USER can be specified in place
of SESSION_USER and CURRENT_USER can be specified in place of CURRENT
USER.
- CURRENT SCHEMA
- Specifies the value of the CURRENT SCHEMA special register at
the time of INSERT, UPDATE, or LOAD as the default for the column.
If CURRENT SCHEMA is specified, the data type of the column must be
a character string with a length greater than or equal to the length
attribute of the CURRENT SCHEMA special register.
- NULL
- Specifies NULL as the default for the column. If NOT NULL was
specified, DEFAULT NULL may be specified within the same column definition
but will result in an error on any attempt to set the column to the
default value.
- cast-function
- This form of a default value can only be used with columns defined
as a distinct type, BLOB or datetime (DATE, TIME or TIMESTAMP) data
type. For distinct type, with the exception of distinct types based
on BLOB or datetime types, the name of the function must match the
name of the distinct type for the column. If qualified with a schema
name, it must be the same as the schema name for the distinct type.
If not qualified, the schema name from function resolution must be
the same as the schema name for the distinct type. For a distinct
type based on a datetime type, where the default value is a constant,
a function must be used and the name of the function must match the
name of the source type of the distinct type with an implicit or explicit
schema name of SYSIBM. For other datetime columns, the corresponding
datetime function may also be used. For a BLOB or a distinct type
based on BLOB, a function must be used and the name of the function
must be BLOB with an implicit or explicit schema name of SYSIBM.
- constant
- Specifies a constant as the argument. The constant must conform
to the rules of a constant for the source type of the distinct type
or for the data type if not a distinct type. If the cast-function is
BLOB, the constant must be a string constant.
- datetime-special-register
- Specifies CURRENT DATE, CURRENT TIME, or CURRENT TIMESTAMP. The
source type of the distinct type of the column must be the data type
that corresponds to the specified special register.
- user-special-register
- Specifies CURRENT USER, SESSION_USER, or SYSTEM_USER. The data
type of the source type of the distinct type of the column must be
a string data type with a length of at least 8 bytes. If the cast-function is
BLOB, the length attribute must be at least 8 bytes.
- CURRENT SCHEMA
- Specifies the value of the CURRENT SCHEMA special register. The
data type of the source type of the distinct type of the column must
be a character string with a length greater than or equal to the length
attribute of the CURRENT SCHEMA special register. If the cast-function
is BLOB, the length attribute must be at least 8 bytes.
- EMPTY_CLOB(), EMPTY_DBCLOB(), or EMPTY_BLOB()
- Specifies a zero-length string as the default for the column.
The column must have the data type that corresponds to the result
data type of the function.
If the value specified is not valid, an error
is returned (SQLSTATE 42894).
- IDENTITY and identity-options
- For specification of identity columns, see IDENTITY and identity-options in "CREATE
TABLE".
- LIKE table-name1 or view-name or nickname
- Specifies that the columns of the table have exactly the same
name and description as the columns of the identified table (table-name1),
view (view-name), or nickname (nickname).
The name specified after LIKE must identify a table, view, or nickname
that exists in the catalog or a declared temporary table. A typed
table or typed view cannot be specified (SQLSTATE 428EC). A protected table cannot be specified (SQLSTATE
42962).A table that has a column
defined as IMPLICITLY HIDDEN cannot be specified (SQLSTATE 560AE).
The
use of LIKE is an implicit definition of
n columns, where
n is
the number of columns in the identified table
(including implicitly
hidden columns), view,
or nickname.
The implicit definition depends on what is identified
after LIKE.- If a table is identified, then the implicit definition includes
the column name, data type and nullability characteristic of each
of the columns of table-name1. If EXCLUDING
COLUMN DEFAULTS is not specified, then the column default is also
included.
- If a view is identified, then the implicit definition includes
the column name, data type, and nullability characteristic of each
of the result columns of the fullselect defined in view-name. The data types of the view columns must be
data types that are valid for columns of a table.
- If a nickname is identified, then the implicit
definition includes the column name, data type, and nullability characteristic
of each column of nickname.
Column
default and identity column attributes may be included or excluded,
based on the
copy-attributes clauses.
The implicit definition does not include any other
attributes of the identified table, view, or nickname. Thus the new
table does not have any unique constraints, foreign key constraints,
triggers, indexes, table partitioning keys,
or distribution keys. The table is created in the table space
implicitly or explicitly specified by the IN clause, and the table
has any other optional clause only if the optional clause is specified.
When
a table is identified in the LIKE clause and that table contains a
ROW CHANGE TIMESTAMP column, the corresponding column of the new table
inherits only the data type of the ROW CHANGE TIMESTAMP column. The
new column is not considered to be a generated column.
If row or column level access control (RCAC)
is enforced for table-name1, RCAC is not inherited
by the new table.
- AS (fullselect)
WITH NO DATA
- Specifies that the columns of the table have the same name and
description as the columns that would appear in the derived result
table of the fullselect if the fullselect were to be executed. The
use of AS (fullselect) is an implicit definition
of n columns for the declared temporary
table, where n is the number of columns
that would result from the fullselect.
The implicit definition
includes the following attributes of the
n columns
(if applicable to the data type):
- Column name
- Data type, length, precision, and scale
- Nullability
The following attributes are not included (the default
value and identity attributes can be included by using the
copy-options):
- Default value
- Identity attributes
- Hidden attribute
- ROW CHANGE TIMESTAMP
The implicit definition does not include any other optional
attributes of the tables or views referenced in the fullselect.
Every
select list element must have a unique name (SQLSTATE 42711). The
AS clause can be used in the select clause to provide unique names.
The fullselect must not refer to host variables or include parameter
markers. The data types of the result columns
of the fullselect must be data types that are valid for columns of
a table.
If row or column level
access control (RCAC) is enforced for any table that is specified
in fullselect, RCAC is not cascaded to the new
table.
- copy-options
- These options specify whether to copy additional attributes of
the source result table definition (table, view, or fullselect).
- INCLUDING COLUMN DEFAULTS
- Column defaults for each updatable column of the source result
table definition are copied. Columns that are not updatable will not
have a default defined in the corresponding column of the created
table.
If LIKE table-name1 is specified,
and table-name1 identifies a base table, created temporary table, or declared temporary
table, then INCLUDING COLUMN DEFAULTS is the default.
- EXCLUDING COLUMN DEFAULTS
- Column defaults are not copied from the source result table definition.
This
clause is the default, except when LIKE table-name is
specified and table-name identifies a base
table, created temporary table, or declared
temporary table.
- INCLUDING IDENTITY COLUMN ATTRIBUTES
- If available, identity column attributes (START WITH, INCREMENT
BY, and CACHE values) are copied from the source's result table definition.
It is possible to copy these attributes if the element of the corresponding
column in the table, view, or fullselect is the name of a column of
a table, or the name of a column of a view which directly or indirectly
maps to the column name of a base table or created
temporary table with the identity property. In all other cases,
the columns of the new temporary table will not get the identity property.
For example:
- The select list of the fullselect includes multiple instances
of the name of an identity column (that is, selecting the same column
more than once)
- The select list of the fullselect includes multiple identity columns
(that is, it involves a join)
- The identity column is included in an expression in the select
list
- The fullselect includes a set operation (union, except, or intersect).
- EXCLUDING IDENTITY COLUMN ATTRIBUTES
- Identity column attributes are not copied from the source result
table definition.
- ON COMMIT
- Specifies the action taken on the global temporary table when
a COMMIT operation is performed. The default is DELETE ROWS.
- DELETE ROWS
- All rows of the table will be deleted if no WITH HOLD cursor is
open on the table.
- PRESERVE ROWS
- Rows of the table will be preserved.
- LOGGED or NOT LOGGED
- Specifies whether operations for the table are
logged. The default is LOGGED.
- LOGGED
- Specifies that insert, update, or delete operations against the
table as well as the creation or dropping of the table are to be logged.
- NOT LOGGED
- Specifies that insert, update, or delete operations against the
table are not to be logged, but that the creation or dropping of the
table is to be logged. During a ROLLBACK (or ROLLBACK TO SAVEPOINT)
operation:
- If the table had been created within a unit of work (or savepoint),
the table is dropped
- If the table had been dropped within a unit of work (or savepoint),
the table is recreated, but without any data
- ON ROLLBACK
- Specifies the action that is to be taken on the not logged global
temporary table when a ROLLBACK (or ROLLBACK TO SAVEPOINT) operation
is performed. The default is DELETE ROWS.
- DELETE ROWS
- If the table data has been changed, all the rows will be deleted.
- PRESERVE ROWS
- Rows of the table will be preserved.
- WITH REPLACE
- Indicates that, in the case that a declared temporary table already
exists with the specified name, the existing table is replaced with
the temporary table defined by this statement (and all rows of the
existing table are deleted).
When WITH REPLACE is not specified,
then the name specified must not identify a declared temporary table
that already exists in the current session (SQLSTATE 42710).
- IN tablespace-name
- Identifies the table space in which the declared temporary
table will be instantiated. The table space must exist and be a USER
TEMPORARY table space (SQLSTATE 42838), over which the authorization
ID of the statement has USE privilege (SQLSTATE 42501). If this clause
is not specified, a table space for the table is determined by choosing
the USER TEMPORARY table space with the smallest sufficient page size
over which the authorization ID of the statement has USE privilege.
When more than one table space qualifies, preference is given according
to who was granted the USE privilege:
- The authorization ID
- A group to which the authorization ID belongs
- PUBLIC
If more than one table space still qualifies, the final choice
is made by the database manager. When no USER TEMPORARY table space
qualifies, an error is raised (SQLSTATE 42727). Determination of
the table space can change when:
- Table spaces are dropped or created
- USE privileges are granted or revoked
The
sufficient page size of a table is determined by either the byte count
of the row or the number of columns. For more details, see "Row
Size" in CREATE TABLE statement.
- distribution-clause
- Specifies the database partitioning or the way the data is distributed
across multiple database partitions.
- DISTRIBUTE BY HASH (column-name, ...)
- Specifies the use of the default hashing function on the specified
columns, called a distribution key, as the distribution method
across database partitions. The column-name must be an unqualified
name that identifies a column of the table (SQLSTATE 42703). The same
column must not be identified more than once (SQLSTATE 42709). No
column whose data type is BLOB, CLOB, DBCLOB,
XML, distinct type based on any of these types, or structured
type can be used as part of a distribution key (SQLSTATE 42962).
If
this clause is not specified, and the table resides in a multiple
partition database partition group with multiple database partitions,
the distribution key is defined as the first column whose data type
is valid for a distribution key.
If none of the columns satisfies
the requirements for a default distribution key, the table is created
without one. Such tables are allowed only in table spaces that are
defined on single-partition database partition groups.
For
tables in table spaces that are defined on single-partition database
partition groups, any collection of columns with data types that are
valid for a distribution key can be used to define the distribution
key. If this clause is not specified, no distribution key is created.
Notes
- A user temporary table space must exist before a declared temporary table can be declared (SQLSTATE
42727).
- Referencing
a declared temporary table: The description of a declared
temporary table does not appear in the database catalog (SYSCAT.TABLES);
therefore, it is not persistent and is not shareable across database
connections. This means that each session that defines a declared
temporary table called table-name has its
own possibly unique description of that declared global temporary
table.
In order to reference the declared temporary table in an
SQL statement (other than the DECLARE GLOBAL TEMPORARY TABLE statement),
the table must be explicitly or implicitly qualified by the schema
name SESSION. If table-name is not qualified
by SESSION, declared temporary tables are not considered when resolving
the reference.
A reference to SESSION.table-name in
a connection that has not declared a declared temporary table by
that name will attempt to resolve from persistent objects in the
catalog. If no such object exists, an error occurs (SQLSTATE 42704).
- When binding a package that has static SQL statements that refer
to tables implicitly or explicitly qualified by SESSION, those statements
will not be bound statically. When these statements are invoked, they
will be incrementally bound, regardless of the VALIDATE option chosen
while binding the package. At runtime, each table reference will be
resolved to a declared temporary table, if it exists, or a created temporary table, or permanent table.
If none exist, an error will be raised (SQLSTATE 42704).
- Privileges: When a declared temporary table is defined,
the definer of the table is granted all table privileges on the table,
including the ability to drop the table. Additionally, these privileges
are granted to PUBLIC. (None of the privileges are granted with the
GRANT option, and none of the privileges appear in the catalog table.)
This enables any SQL statement in the session to reference a declared
temporary table that has already been defined in that session.
- Instantiation and termination: For the following
explanations, P denotes a session and T is a declared temporary table
in the session P:
- An empty instance of T is created as a result of the DECLARE GLOBAL
TEMPORARY TABLE statement that is executed in P.
- Any SQL statement in P can make reference to T and any reference
to T in P is a reference to that same instance of T.
- If a DECLARE GLOBAL TEMPORARY TABLE statement is specified within
the SQL procedure compound statement (defined by BEGIN and END), the
scope of the declared temporary table is the connection, not just
the compound statement, and the table is known outside of the compound
statement. The table is not implicitly dropped at the END of the compound
statement. A declared temporary table cannot be defined multiple times
by the same name in other compound statements in that session, unless
the table has been explicitly dropped.
- Assuming that the ON COMMIT DELETE ROWS clause was specified implicitly
or explicitly, then when a commit operation terminates a unit of work
in P, and there is no open WITH HOLD cursor in P that is dependent
on T, the commit includes the operation DELETE FROM SESSION.T.
- When a rollback operation terminates a unit of work or a savepoint
in P, and that unit of work or savepoint includes a modification to
SESSION.T:
- If
NOT LOGGED was specified, all rows from SESSION.T are deleted unless
ON ROLLBACK PRESERVE ROWS was also specified
- If NOT LOGGED was not specified, the changes to T are undone
- If
NOT LOGGED was specified and an INSERT, UPDATE or DELETE statement
fails during execution (as opposed to a compilation error), all rows
from SESSION.T are deleted.
- When a rollback operation terminates a unit of work or a savepoint
in P, and that unit of work or savepoint includes the declaration
of SESSION.T, then the rollback includes the operation DROP SESSION.T.
- If a rollback operation terminates a unit of work or a savepoint
in P, and that unit of work or savepoint includes the drop of a declared
temporary table SESSION.T, then the rollback will undo the drop of
the table. If NOT LOGGED was specified, then the table will also have
been emptied.
- When the application process that declared T terminates or disconnects
from the database, T is dropped and its instantiated rows are destroyed.
- When the connection to the server at which T was declared terminates,
T is dropped and its instantiated rows are destroyed.
- Restrictions on the use of declared temporary tables: Declared
temporary tables cannot:
- Be specified in an ALTER, COMMENT, GRANT, LOCK, RENAME or REVOKE
statement (SQLSTATE 42995).
- Be referenced in an AUDIT, CREATE ALIAS,
or CREATE VIEW statement (SQLSTATE 42995).
- Be specified in referential constraints (SQLSTATE 42995).
- Data row compression is enabled for a declared
temporary table. When the database manager determines that there is
a performance gain, table row data including XML documents stored
inline in the base table object will be compressed. However, data
compression of the XML storage object of a declared temporary table
is not supported.
- Index compression is enabled for indexes that
are created on declared temporary tables.
- Index
compression is enabled by default for indexes that are created on declared temporary tables.
Compression will be shown as on, but indexes will not be compressed if the correct license (IBM DB2
Storage Optimization Feature) is not applied.
- Syntax
alternatives: The following syntax alternatives are
supported for compatibility with previous versions of DB2® and
with other database products. These alternatives are non-standard and should
not be used.
- DEFINITION ONLY can be specified in
place of WITH NO DATA
- The PARTITIONING KEY clause can be specified in place of the DISTRIBUTE BY clause
The following syntax is accepted as the default behavior:
- CCSID ASCII
- CCSID UNICODE
Examples
- Example 1: Define a declared temporary table with column
definitions for an employee number, salary, bonus, and commission.
DECLARE GLOBAL TEMPORARY TABLE SESSION.TEMP_EMP
(EMPNO CHAR(6) NOT NULL,
SALARY DECIMAL(9, 2),
BONUS DECIMAL(9, 2),
COMM DECIMAL(9, 2)) ON COMMIT PRESERVE ROWS
- Example 2: Assume that base table USER1.EMPTAB exists and
that it contains three columns, one of which is an identity column.
Declare a temporary table that has the same column names and attributes
(including identity attributes) as the base table.
DECLARE GLOBAL TEMPORARY TABLE TEMPTAB1
LIKE USER1.EMPTAB
INCLUDING IDENTITY
ON COMMIT PRESERVE ROWS
In this example, SESSION
is used as the implicit qualifier for TEMPTAB1.