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  1. #1
    3 Star Lounger
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    Two small Questions (Acc 97 sr2 on 95b)

    I have been reading the post digest and have these 2 questions out of it.

    When you talk about split databases and making the front-end MDE read only, do you just mean set the file attribute or is there an internal setting that is set before compiling the MDE?

    Wendell was also talking about copying the back-end for backup purposes. Can this be done safely while the file is open via 1 or more front-ends? I have a copy of Iomega's QuikSync 3 set to copy the back-end at 6pm each day and I would like to be able to do this more frequently, approx every 3 hours.

    HMMMM <img src=/S/thinks.gif border=0 alt=thinks width=15 height=15> Is a back-end file actually opened when being accessed by a front-end?
    Is a back-end file considered modified after any write to it from a front end?
    Could I get a corrupted copy if the back-end is copied while being written to?

    Do I really know what I'm doing? <img src=/S/shrug.gif border=0 alt=shrug width=39 height=15>

    Regards, Allan <img src=/S/aussie.gif border=0 alt=aussie width=21 height=22>
    "Heading for the deep end"

  2. #2
    Plutonium Lounger
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    Re: Two small Questions (Acc 97 sr2 on 95b)

    Alan,

    Addressing the last question, yes, the backend database is open when it's being accessed by the front-end. Certainly, the data is modified after a write from the front end. There isn't any other reason *to* write to the back end, after all. I would not recommend trying to copy the database while it was being written to. In fact, in Access 2000, that isn't allowed.
    Charlotte

  3. #3
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    Re: Two small Questions (Acc 97 sr2 on 95b)

    You wrote:
    >>When you talk about split databases and making the front-end MDE read only, do you just mean set the file attribute or is there an internal setting that is set before compiling the MDE?<<

    You can't make the frontend read-only. Access has to be able to write to the database for some of its housekeeping. Well, I guess you actually can physically do it, but making a .mde database read-only serves no practical purpose anyway.
    Mark Liquorman
    See my website for Tips & Downloads and for my Liquorman Utilities.

  4. #4
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    Re: Two small Questions (Acc 97 sr2 on 95b)

    I got up late today obviously! As to setting front-end .mde files to READ-ONLY, there are actually a couple of pretty good reasons. First, it stops all the bloat that occurs in an Access2k database that is being used as a front-end and is never updated. Second, it prevents Access from updating the date modified for the .mde file, so you can tell exactly when a given front-end file was created. Third, it solves all of the corruption problems that occur when somebody locks up their PC and decides to re-boot while they were working in a front-end. We started this shortly after we went to Access2k and it resolved a number of problems, and at this point we haven't found a down-side to it. Obviously not every front-end can be done that way, but it works really well with add-in databases which we use in many applications. As to the question about how to do it, we typically set the file attribute, but you could also do it via a short-cut with one of the command line options. That would give you the flexibility of starting it with edit capabilities should you want to. Otherwise you have to turn off the file attribute bit.

    As to the prior question about copying a .mdb file, Charlotte is correct that Access2k won't let you do it if the file is actively being updated, but the copy routine know that and simply waits until the write lock has been released before it takes a snapshot of the file. Access97 is a bit more fragile in that respect, so I would be very cautious about copying Jet 3x files. We frankly don't do it very often that way because we usually have SQL back-end rather than a Jet file. Hope this clarifies things a bit.
    Wendell

  5. #5
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    Re: Two small Questions (Acc 97 sr2 on 95b)

    I personally prefer to put a routine in the startup folder which copies the current version of the .mde file down from the server to local disk. This handles all the problems you mentioned, plus keeps the frontend current.
    Mark Liquorman
    See my website for Tips & Downloads and for my Liquorman Utilities.

  6. #6
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    Re: Two small Questions (Acc 97 sr2 on 95b)

    Actually we do something similar. Each workstation runs a custom app that is used to start databases. Then each time a user opens a given database, we check to make sure they have the latest front-end on their local hard drive, and if they don't we download it. We also check components such as the Windows Common Controls and update them if necessary. But people can still corrupt the local front-end with a system crash or some form of tinkering if the local file can be modified, so we ended up making the really critical things READ-ONLY and that has reduced our support effort by a considerable amount. It also makes it easy to deploy a set of changes when we do maintenance or new development.

    Obviously you can't do the READ-ONLY bit if you are modifying local tables, or if the user is allowed to create ad-hoc queries and save them. That's the only real down side to putting the front-end on the local hard drive - you wipe out any new objects a user may have created. But all in all, with the performance gains and the reduction in support, we think it's the only way to go.
    Wendell

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