study note db2

ISOLATION LEVEL RR, RS, CS, or UR
Specifies how far to isolate the routine from the effects of other running applications. For information about isolation levels, see DB2 Performance Monitoring and Tuning Guide.
RR
Specifies repeatable read.
RS
Specifies read stability.
CS
Specifies cursor stability. CS is the default.
UR
Specifies uncommitted read.

FOR UPDATE CLAUSE OPTIONAL or FOR UPDATE CLAUSE REQUIRED
Specifies whether the FOR UPDATE clause is required for a DECLARE CURSOR statement if the cursor is to be used to perform positioned updates.
FOR UPDATE CLAUSE REQUIRED
Specifies that a FOR UPDATE clause must be specified as part of the cursor definition if the cursor will be used to make positioned updates.

FOR UPDATE CLAUSE REQUIRED is the default.
FOR UPDATE CLAUSE OPTIONAL
Specifies that the FOR UPDATE clause does not need to be specified in order for a cursor to be used for positioned updates. The routine body can include positioned UPDATE statements that update columns that the user is authorized to update.
The FOR UPDATE clause with no column list applies to static or dynamic SQL statements. Even if you do not use this clause, you can specify FOR UPDATE OF with a column list to restrict updates to only the columns that are named in the FOR UPDATE clause and to specify the acquisition of update locks.