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Sybase 12.4.2 User Manual

Page 141

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CHAPTER 3 Working with Database Objects

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WHERE l_discount < 0.5

You declare a local temporary table for your connection only, using the

DECLARE LOCAL TEMPORARY TABLE

statement. A local temporary table

exists until the connection ends, or within a compound statement in which it is
declared. The table and its data are completely inaccessible to other users.

See “Versioning of temporary tables” for versioning information on local
temporary tables.

Dropping and altering
global temporary
tables

You drop a global temporary table just as you would a base table, with the

DROP TABLE

statement, or with the Sybase Central table editor. You cannot

drop or alter a global temporary table while other connections are using the
table it.

Placement of tables

Adaptive Server IQ creates tables in your current database. If you are
connected to an IQ database, tables are placed as follows:

Table 3-2: Table placement

Join virtual tables

A Join Virtual Table is a denormalized table that looks like a regular table; it
has a name, columns, rows, and indexes. Adaptive Server IQ creates Join
Virtual Tables as a result of a Create Join Index for internal processing
purposes and deletes them when you do a Drop Join Index. You cannot create,
modify, or delete Join Virtual Tables, but you may see error messages related
to them if you try to use or modify them. Sybase suggests that you ignore all
Join Virtual Tables.

Automatic index creation for IQ tables

You can automate indexing for certain columns by creating a table with either

PRIMARY KEY

or

UNIQUE

as a single-column constraint. These options cause

Adaptive Server IQ to create an

HG

index for the column that enforces

uniqueness.

Type of table

Permitted placement

Default placement

Permanent

Main IQ Store or Catalog
Store

Main IQ Store

Global temporary

Temporary IQ Store or
Catalog Store

Temporary IQ Store

Local temporary

Temporary IQ Store or
Catalog Store; only visible
to user who creates it

Temporary IQ Store