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PostgreSQL documentation

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<para>

Although the syntax of <literal>CREATE TEMPORARY TABLE</literal>

resembles that of SQL92, the effect is not the same. In the standard,

temporary tables are associated with modules; a temporary table is created

just once and automatically exists (starting with empty contents) in every

session that uses the module.

<productname>PostgreSQL</productname> does not have modules, and

temporary tables are defined just once and automatically exist (starting

with empty contents) in every session that needs them.

<productname>PostgreSQL</productname> instead

requires each session to issue its own <literal>CREATE TEMPORARY

TABLE</literal> command for each temporary table to be used.

The notion of <literal>GLOBAL</literal> temporary tables found in SQL92

is not in <productname>PostgreSQL</productname> at all.

TABLE</literal> command for each temporary table to be used. This allows

different sessions to use the same temporary table name for different

purposes, whereas the spec's approach constrains all instances of a

given temporary table name to have the same table structure.

</para>

<note>

</para>

</note>

<para>

SQL92's distinction between global and local temporary tables

is not in <productname>PostgreSQL</productname>, since that distinction

depends on the concept of modules, which

<productname>PostgreSQL</productname> does not have.

</para>

<para>

The <literal>ON COMMIT</literal> clause for temporary tables

also resembles SQL92, but has some differences.

If the <literal>ON COMMIT</> clause is omitted, SQL92 specifies that the

default behavior is <literal>ON COMMIT DELETE ROWS</>. However, the

default behavior in <productname>PostgreSQL</productname> is

<literal>ON COMMIT PRESERVE ROWS</literal>. The <literal>ON COMMIT

DROP</literal> option does not exist in SQL92 at all.

DROP</literal> option does not exist in SQL92.

</para>

</refsect2>