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Transparent Persistence/Activation

Last post 08-29-2008, 05:49 AM by Tetyana Loskutova. 7 replies.
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  •  08-26-2008, 12:57 PM 50769

    Transparent Persistence/Activation

    is it safe to use transparent Activation/Persistence with Version 7.2 ?

    I want to use db4o for educational purposes, and I do not want to get into problems, that do not originate in the students'  code.

    Ingeborg Liedlbauer

     

     

  •  08-27-2008, 05:20 AM 50778 in reply to 50769

    Re: Transparent Persistence/Activation

    Hi,

    you can find this hint on the donwloadpage: http://developer.db4o.com/files/folders/db4o_72/default.aspx 

    db4o 7.2 

    Please, note that Transparent Activation/Persistence are not production-ready in this release yet.

    But I don´t know more about the current releases.

    Hope it could help.

     
    best regards Origon
     

     


    Germany
  •  08-27-2008, 08:08 AM 50782 in reply to 50769

    Re: Transparent Persistence/Activation

    Ingeborg,

     Although it's not production ready currently, it works reasonably well. You have to be aware of some issues:

    - Forgetting to enhance certain assemblies can cause bugs which are strange to debug.

    - Sometimes you will not be able to debug enhanced assemblies.

  •  08-27-2008, 01:31 PM 50796 in reply to 50782

    Re: Transparent Persistence/Activation

    Andrei,
      I tried TP/A with our fairly large application, enhancing only the classes that are persisted, ran into a lot of problems and gave up, waiting for it to be officially released with clear documentation. What do you mean by "assemblies"?
        Scott
  •  08-27-2008, 03:43 PM 50802 in reply to 50796

    Re: Transparent Persistence/Activation

    Scott Reed wrote:
    > I tried TP/A with our fairly large application,
    > enhancing only the classes that are persisted,

    Makes sense but please note:
    If you change members of objects that are persisted
    elsewhere in your code, db4o has no way of knowing
    about the changes.


    > ran into a lot of problems and gave up,

    It would be cool if you could tell us about the
    problems, so we can improve.

    Whenever you run across a problem, please tell
    us first.

    Whenever you think db4o is nice, please tell
    the world out there.



    > What do you mean by "assemblies"?

    Probably .NET assemblies.

    Maybe you are a Java user? The equivalent would
    be "Java .jars".
  •  08-27-2008, 05:33 PM 50807 in reply to 50802

    Re: Transparent Persistence/Activation

    Carl Rosenberger wrote:
    >Scott Reed wrote:
    >> I tried TP/A with our fairly large application,
    >> enhancing only the classes that are persisted,
    >
    >Makes sense but please note:
    >If you change members of objects that are persisted
    >elsewhere in your code, db4o has no way of knowing
    >about the changes.

    All non-final data members are private and only modifiable from elsewhere in the code only via method calls.

    >> ran into a lot of problems and gave up,
    >
    >It would be cool if you could tell us about the
    >problems, so we can improve.
    >
    >Whenever you run across a problem, please tell
    >us first.

    I mentioned this in an earlier post (VerifyError with Db4oInstrumentationLauncher). Patrick asked me to send in the code but it was difficult to isolate. It's a large code base and mostly proprietary. We need to know more about your policies and procedures in handling customer code before we could send anything in.

    >Whenever you think db4o is nice, please tell
    >the world out there.

    Definitely. I'm believer! I've been using db4o since the mid-90's.

    >> What do you mean by "assemblies"?
    >
    >Probably .NET assemblies.
    >
    >Maybe you are a Java user? The equivalent would
    >be "Java .jars".

    Yes, I've had no experience with .net at all except the unhappy experience of trying to install multiple versions for a couple of VB projects.

  •  08-28-2008, 09:19 PM 50824 in reply to 50807

    Re: Transparent Persistence/Activation

    I started using transparent activation / persistence a few months ago using 7.4 and so far I have not found any problems.

    The most difficult task I had was modifying the Netbeans Ant build file to incorporate the enhancement task.  This was entirely due to my lack of knowledge about Ant!  Though perhaps Db4o could help by including an example of a modified Netbeans build.xml file in the documentation.  I would be happy to supply a copy of my build file if it would help.

    Regards
    Graham

  •  08-29-2008, 05:49 AM 50826 in reply to 50824

    Re: Transparent Persistence/Activation

    Hi Graham!

    Thanks for suggestion - I will definitely do so. Can you please send me your build file?

    Thanks!

    Tetyana 

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