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Oracle temporary tables are divided into session-level temporary tables and transaction-level temporary tables.

Session-level temporary table means that the data in the temporary table only exists in the session life cycle. When the user exits and the session ends, Oracle automatically clears the temporary table data.

A transaction-level temporary table means that the data in the temporary table exists only in the transaction life cycle. When a transaction ends (commit or rollback), Oracle automatically clears the data in the temporary table.

The data in the temporary table is only valid for the current Session, each Session has its own temporary data, and cannot access the data in the temporary table of other Session. therefore,

Temporary watches do not require DML locks. When a session ends (the user exits normally, the user exits abnormally and the ORACLE instance crashes) or when a transaction ends, Oracle responds to the

The table executes the TRUNCATE statement to empty the temporary table data. However, the data in other session temporary tables will not be emptied.

You can index temporary tables and create views based on temporary tables. Similarly, indexes built on temporary tables are temporary and valid only for the current session or transaction.

Temporary tables can have triggers.

one. Session-specific temporary tables

CREATE GLOBAL TEMPORARY ()

ON COMMIT PRESERVE ROWS

two. Transaction-specific temporary table

CREATE GLOBAL TEMPORARY ()

ON COMMIT DELETE ROWS

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