Application Development Guide

Isolation Levels

DB2 Connect accepts the following isolation levels when you prep or bind an application:

RR

Repeatable Read

RS

Read Stability

CS

Cursor Stability

UR

Uncommitted Read

NC

No Commit

The isolation levels are listed in order from most protection to least protection. If the host or AS/400 server does not support the isolation level that you specify, the next higher supported level is used.

Table 55 shows the result of each isolation level on each host or AS/400 application server.

Table 55. Isolation Levels

DB2 Connect	DB2 Universal Database for OS/390	DB2 for VSE & VM	DB2 Universal Database for AS/400	DB2 Universal Database
RR	RR	RR	note 1	RR
RS	note 2	RR	COMMIT(*ALL)	RS
CS	CS	CS	COMMIT(*CS)	CS
UR	note 3	CS	COMMIT(*CHG)	UR
NC	note 4	note 5	COMMIT(*NONE)	UR
Notes: There is no equivalent COMMIT option on DB2 Universal Database for AS/400 that matches RR. DB2 Universal Database for AS/400 supports RR by locking the whole table. Results in RR for Version 3.1, and results in RS for Version 4.1 with APAR PN75407 or Version 5.1. Results in CS for Version 3.1, and results in UR for Version 4.1 or Version 5.1. Results in CS for Version 3.1, and results in UR for Version 4.1 with APAR PN60988 or Version 5.1. Isolation level NC is not supported with DB2 for VSE & VM.

With DB2 Universal Database for AS/400, you can access an unjournalled table if an application is bound with an isolation level of UR and blocking set to ALL, or if the isolation level is set to NC.