DB2 10.5 for Linux, UNIX, and Windows

DECLARE GLOBAL TEMPORARY TABLE statement

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.