IBM 000-8697 Manual de usuario descargar pdf (Pagina 207)

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System Architecture 2-113

Create a Temporary Table: What Happens on Disk

After the root dbspace exists, users with the necessary SQL privileges can

create an explicit temporary table by executing the SQL statement CREATE

TABLE

with the TEMP keyword. During processing, OnLine user processes

may create implicit temporarytables aspart of SQL statementprocessing.If a

user creates a temporary table by executing a SELECT ... INTO TEMP

statement, OnLinehandles thetable as if it werean explicit temporary table.

Placement

By default, temporary tables are created in the root dbspace.

Users can create explicit temporary tables in some other dbspace by speci-

fying the dbspace name in the CREATE TABLE statement. Users can also

specify sizes of the initial extent and the next extents for an explicit

temporary table in the statement. If initial and next extent sizes are not

speciﬁed, the default sizes are eight pages.

Temporary tables created as part of internal processing or by using the

SELECT ... INTO TEMP statement always reside in the root dbspace. For an

implicit temporary table, the initial and next extent sizes are always eight

pages.

Tracking

The tasks involved in creating temporary tables are similar to the tasks

OnLine performswhen it adds a newpermanent table. The key differenceis

that temporary tables do not receive an entry in the system catalog for the

database.(Refertopage 2-110foradescriptionofwhathappenswhenatable

is created.)

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