FOR UPDATE

Description

SELECT and lock rows for possible update within the current transaction

Versions

This operation is implemented in the following versions

7.3.4
8.0.4
8.0.5
8.0.6
8.1.5
8.1.6
8.1.7
9.0.1
9.2.0
10.1.0
10.2.0

Example

This example was developed using Oracle 9.2.0.1 on Windows 2000

This example requires the following table definition

    CREATE TABLE t1 (c1 NUMBER);

The table does not need to be analysed

The statement

    SELECT c1 FROM t1 FOR UPDATE;

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   FOR UPDATE
2   1     TABLE ACCESS (FULL) OF 'T1'