Re: cayenne & distributed databases

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Thu Nov 06 2003 - 11:04:35 EST

  • Next message: Mike Kienenberger: "Re: distributed transactions"

    Hi Martin,

    Let me add a few things to what Mike has said.

    > - does cayenne cayenne map any changes made within a datacontext to one
    > physical database transaction, containing all generated sql
    > statements, or is
    > each statement commited individually?

    Each call to DataContext.commitChanges() will always start a new
    transaction and commit all changes atomically within this transaction.

    > - does cayenne support any locking policys, e.g. optimistic locking,
    > pessimistic locking?

    See Mike's comment...

    > - does cayenne support distributed database access (access to dbs,
    > which are
    > hosted on different physical servers)? and if so, how about distributed
    > transactions?

    Cayenne definitely supports access of multiple databases from the same
    DataContext. I believe there is still an (easy to fix) issue in the
    DataContext underlying commit mechanism that internally commits
    individual DB transactions independently. It is on my list of things to
    fix.

    Interaction with JTA is planned for 1.1.

    Thanks
    Andrus

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