CURRENT ISOLATION special register

The CURRENT ISOLATION special register holds a CHAR(2) value that identifies the isolation level (in relation to other concurrent sessions) for any dynamic SQL statements issued within the current session.

The possible values are:
(blanks)
Not set; use the isolation attribute of the package.
UR
Uncommitted Read
CS
Cursor Stability
RR
Repeatable Read
RS
Read Stability

The value of the CURRENT ISOLATION special register can be changed by the SET CURRENT ISOLATION statement.

Until a SET CURRENT ISOLATION statement is issued within a session, or after RESET has been specified for SET CURRENT ISOLATION, the CURRENT ISOLATION special register is set to blanks and is not applied to dynamic SQL statements; the isolation level used is taken from the isolation attribute of the package which issued the dynamic SQL statement. Once a SET CURRENT ISOLATION statement has been issued, the CURRENT ISOLATION special register provides the isolation level for any subsequent dynamic SQL statement compiled within the session, regardless of the settings for the package issuing the statement. This will remain in effect until the session ends or until a SET CURRENT ISOLATION statement is issued with the RESET option.

Example: Set the host variable ISOLATION_MODE (CHAR(2)) to the value currently stored in the CURRENT ISOLATION special register. 
   VALUES CURRENT ISOLATION
     INTO :ISOLATION_MODE