SET TXLEVEL

Purpose

To set the current transaction level

Syntax

SET TRANSACTION UNCOMMITTED | COMMITTED

See Also

CLOSE, Configuration Files, DECLARE CURSOR, DROP CURSOR, FETCH, OPEN, SELECT, TXLEVEL(), TXNISOLATION(), TXNLEVEL()

Description

Three aspects of transaction behavior are configurable: dirty reads, non-repeatable reads and phantom reads. Dirty reads occur when a transaction updates a row, then a second transaction reads that row before the first transaction commits. If the first transaction rolls back the change, the information read by the second transaction becomes invalid. Non-repeatable reads occur when a transaction reads a row then another transaction updates the same row. If the second transaction commits, subsequent reads by the first transaction get different values than the original read. Phantoms occur when a transaction reads a set of rows that satisfy a search condition and then another transaction updates, inserts, or deletes one or more rows that satisfy the first transaction’s search condition. In this case, if the first transaction performs subsequent reads with the same search condition, it reads a different set of rows.

Keywords	Description
UNCOMMITTED	This will enable dirty reads, non-repeatable reads and phantom reads. This is the default.
COMMITTED	This will disable dirty reads and enable non-repeatable reads and phantom reads.

Example

set txlevel committed

Products

Recital Server, Recital