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— Statements —

BACKOUT TRANSACTION

BACKOUT [TRANSACTION]

This document covers the following topics:

Function
Restriction
Database-Specific Considerations
Example

For an explanation of the symbols used in the syntax diagram, see Syntax Symbols.

Belongs to Function Group: Database Access and Update

Function

The BACKOUT TRANSACTION statement is used to back out all database updates performed during the current logical transaction. This statement also releases all records held during the transaction.

The statement is executed only if a database transaction under control of Natural has taken place. For which databases the statement is executed depends on the setting of the profile parameter ET (execution of END/BACKOUT TRANSACTION statements):

If ET=OFF, the statement is executed only for the database affected by the transaction.
If ET=ON, the statement is executed for all databases that have been referenced since the last execution of a BACKOUT TRANSACTION or END TRANSACTION statement.

Backout Transaction Issued by Natural

If the user interrupts the current Natural operation with a terminal command (command %% or CLEAR key), Natural issues a BACKOUT TRANSACTION statement.

See also the terminal command %% in the Terminal Commands documentation.

Additional Information

For additional information on the use of the transaction backout feature, see the sections Database Update - Transaction Processing and Backing Out a Transaction in the Programming Guide.

Restriction

This statement is not available with Entire System Server.

Database-Specific Considerations

DL/I Databases Because PSB scheduling is terminated by a syncpoint request, Natural saves the PSB position before executing the BACKOUT TRANSACTION statement. Before the next command execution, Natural re-schedules the PSB and tries to set the PCB position as it was before the backout. The PCB position might be shifted forward if any pointed segment had been deleted in the time period between the backout and the following command.

SQL Databases As most SQL databases close all cursors when a logical unit of work ends, a BACKOUT TRANSACTION statement must not be placed within a database modification loop; instead, it has to be placed after such a loop.

DL/I Databases	Because PSB scheduling is terminated by a syncpoint request, Natural saves the PSB position before executing the `BACKOUT TRANSACTION` statement. Before the next command execution, Natural re-schedules the PSB and tries to set the PCB position as it was before the backout. The PCB position might be shifted forward if any pointed segment had been deleted in the time period between the backout and the following command.
SQL Databases	As most SQL databases close all cursors when a logical unit of work ends, a `BACKOUT TRANSACTION` statement must not be placed within a database modification loop; instead, it has to be placed after such a loop.

Example

** Example 'BOTEX1': BACKOUT TRANSACTION                                
**                                                                      
** CAUTION: Executing this example will modify the database records!    
************************************************************************
DEFINE DATA LOCAL                                                       
1 EMPLOY-VIEW VIEW OF EMPLOYEES                                         
  2 NAME                                                                
  2 DEPT                                                                
  2 LEAVE-DUE                                                           
  2 LEAVE-TAKEN                                                         
*                                                                       
1 #DEPT (A6)                                                            
1 #RESP (A3)                                                            
END-DEFINE                                                              
*                                                                       
LIMIT 3                                                                 
INPUT 'DEPARTMENT TO BE UPDATED:' #DEPT                                 
IF #DEPT = ' '                                                          
  STOP                                                                  
END-IF                                       
*                                            
FIND EMPLOY-VIEW WITH DEPT = #DEPT           
  IF NO RECORDS FOUND                        
    REINPUT 'NO RECORDS FOUND'               
  END-NOREC                                  
  INPUT 'NAME:       ' NAME (AD=O) /         
        'LEAVE DUE:  ' LEAVE-DUE (AD=M) /    
        'LEAVE TAKEN:' LEAVE-TAKEN (AD=M)    
  UPDATE                                     
END-FIND                                     
*                                            
INPUT 'UPDATE TO BE PERFORMED? YES/NO:' #RESP
DECIDE ON FIRST #RESP                        
  VALUE 'YES'                                
    END TRANSACTION                          
  VALUE 'NO'                                 
    BACKOUT TRANSACTION                      
  NONE                                       
    REINPUT 'PLEASE ENTER YES OR NO' 
END-DECIDE
*                                    
END

Output of Program BOTEX1:

DEPARTMENT TO BE UPDATED: MGMT30

Result for department MGMT30:

NAME:        POREE
LEAVE DUE:   45
LEAVE TAKEN: 31

Confirmation query:

UPDATE TO BE PERFORMED  YES/NO: NO

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