[Torque] SELECT for UPDATE

From: T.E. Schmitz (nospam_at_nowhere.com)
Date: 04/23/04

  • Next message: T.E. Schmitz: "[Torque] SELECT for UPDATE" 
    Date: Fri, 23 Apr 2004 18:21:50 +0100

    As far as I can see there is no means of doing a SELECT for UPDATE in
    Torque, i.e. it is not possible to lock a record in a transaction.

    I need a locking read for the following reason:
    Every record is marked with a 'LastUpdated' timestamp in order to enable
    checking whether it has been updated in the meantime in another session.
    Prior to any UPDATE or DELETE the record is re-read and timestamps are
    compared. If the SELECT doesn't return any results the record has been
    deleted. If the timestamp has changed the record has been modified in
    the meantime. For this to work, the record needs to be locked by the
    SELECT operation; otherwise there is still a window between the SELECT
    and the UPDATE during which another session could modify or delete it.

    Also, this is the only way of knowing whether the UPDATE has been
    successful because Torque's doUpdate doesn't return the number of
    effected rows.

    Has anybody found a work-around for this problem? 

    -- 
Regards,
Tarlika Elisabeth Schmitz
  • Next message: T.E. Schmitz: "[Torque] SELECT for UPDATE"

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