Difference between revisions of "BEGIN TRANSACTION"

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=BEGIN TRANSACTION=
 
 
 
==Class==
 
Transaction Processing
 
 
 
 
==Purpose==
 
==Purpose==
 
Begin transaction Before Image Journaling
 
Begin transaction Before Image Journaling
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==See Also==
 
==See Also==
[[COMPLETED()]], [[ISMARKED()]], [[RESET IN]], [[ROLLBACK]], [[ROLLBACK()]], [[SET ROLLBACK]]
+
[[COMPLETED()]], [[END TRANSACTION]], [[ISMARKED()]], [[RESET IN]], [[ROLLBACK]], [[ROLLBACK()]], [[SET ROLLBACK]]
  
  
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The BEGIN TRANSACTION command is used to flag the beginning of a transaction for Before Image Journaling (BIJ).  A 'transaction' consists of all file modifications that occur within the commands BEGIN TRANSACTION and END TRANSACTION.
 
The BEGIN TRANSACTION command is used to flag the beginning of a transaction for Before Image Journaling (BIJ).  A 'transaction' consists of all file modifications that occur within the commands BEGIN TRANSACTION and END TRANSACTION.
  
When BEGIN TRANSACTION is issued all currently open files and all files opened between BEGIN and END TRANSACTION will have BIJ invoked automatically.  If BIJ is not required on a particular table then the RESET IN command should be issued for the relevant workarea so that journaling will no longer occur in that workarea.  The journals are stored in a log file (with a file extension of '.log'') which the Recital/4GL generates automatically.  You can optionally specify the disk and directory <path name> where the log file will be stored when the BEGIN TRANSACTION command is issued.
+
When BEGIN TRANSACTION is issued all currently open files and all files opened between BEGIN and END TRANSACTION will have BIJ invoked automatically.  If BIJ is not required on a particular table then the RESET IN command should be issued for the relevant workarea so that journaling will no longer occur in that workarea.  The journals are stored in a log file (with a file extension of '.log') which the Recital/4GL generates automatically.  You can optionally specify the disk and directory <path name> where the log file will be stored when the BEGIN TRANSACTION command is issued.
  
 
A "rollback" causes record contents to be restored to their value before modification (i.e. at the time BEGIN TRANSACTION was issued).  This is particularly useful if an error occurs during a program that modifies files.
 
A "rollback" causes record contents to be restored to their value before modification (i.e. at the time BEGIN TRANSACTION was issued).  This is particularly useful if an error occurs during a program that modifies files.
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Please note that the following commands are not allowed during a transaction:
 
Please note that the following commands are not allowed during a transaction:
  
*CLEAR ALL
+
 
*CLOSE ALL
+
*[[CLEAR ALL]]
*CLOSE DATABASE
+
*[[CLOSE ALL]]
*CLOSE INDEX
+
*[[CLOSE DATABASES]]
*MODIFY STRUCTURE
+
*[[CLOSE INDEX]]
*PACK
+
*[[MODIFY STRUCTURE]]
*ZAP
+
*[[PACK]]
 +
*[[ZAP]]
  
  
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<code lang="recital">
 
<code lang="recital">
 
procedure recovery
 
procedure recovery
 +
 
rollback
 
rollback
 
if rollback()
 
if rollback()
dialog box "Rollback was ok."
+
    dialog box "Rollback was ok."
 
else
 
else
dialog box "Rollback not completed."
+
    dialog box "Rollback not completed."
 
endif
 
endif
 +
 
return
 
return
  
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on error do recovery
 
on error do recovery
 
begin transaction
 
begin transaction
delete first 15
+
    delete first 15
insert
+
    insert
replace all t1 with (t2*t3)/100
+
    replace all t1 with (t2*t3)/100
list
+
    list
 
end transaction
 
end transaction
 
if completed()
 
if completed()
dialog box "Transaction completed"
+
    dialog box "Transaction completed"
 
else
 
else
dialog box "Errors occurred during transaction"
+
    dialog box "Errors occurred during transaction"
 
endif
 
endif
 
</code>
 
</code>
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==Products==
 
==Products==
Recital Database Server, Recital Mirage Server, Recital Terminal Developer
+
Recital Server, Recital  
 
[[Category:Documentation]]
 
[[Category:Documentation]]
 
[[Category:Commands]]
 
[[Category:Commands]]
 +
[[Category:Transaction Processing]]
 +
[[Category:Transaction Processing Commands]]

Latest revision as of 14:36, 10 November 2009

Purpose

Begin transaction Before Image Journaling


Syntax

BEGIN TRANSACTION [<path name>]

<commands>

END TRANSACTION


See Also

COMPLETED(), END TRANSACTION, ISMARKED(), RESET IN, ROLLBACK, ROLLBACK(), SET ROLLBACK


Description

The BEGIN TRANSACTION command is used to flag the beginning of a transaction for Before Image Journaling (BIJ). A 'transaction' consists of all file modifications that occur within the commands BEGIN TRANSACTION and END TRANSACTION.

When BEGIN TRANSACTION is issued all currently open files and all files opened between BEGIN and END TRANSACTION will have BIJ invoked automatically. If BIJ is not required on a particular table then the RESET IN command should be issued for the relevant workarea so that journaling will no longer occur in that workarea. The journals are stored in a log file (with a file extension of '.log') which the Recital/4GL generates automatically. You can optionally specify the disk and directory <path name> where the log file will be stored when the BEGIN TRANSACTION command is issued.

A "rollback" causes record contents to be restored to their value before modification (i.e. at the time BEGIN TRANSACTION was issued). This is particularly useful if an error occurs during a program that modifies files.

If SET ROLLBACK is ON, the Recital/4GL will automatically execute the ROLLBACK command if an error occurs during the transaction process. Otherwise, error trapping should be handled manually using the ON ERROR command.

The COMPLETED() function can be used after the END TRANSACTION command to determine if any errors occurred during processing of the commands between BEGIN and END TRANSACTION.

Please note that the following commands are not allowed during a transaction:



Example

procedure recovery
 
rollback
if rollback()
    dialog box "Rollback was ok."
else
    dialog box "Rollback not completed."
endif
 
return
 
use accounts
on error do recovery
begin transaction
    delete first 15
    insert
    replace all t1 with (t2*t3)/100
    list
end transaction
if completed()
    dialog box "Transaction completed"
else
    dialog box "Errors occurred during transaction"
endif


Products

Recital Server, Recital