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Thread: DAO to ADO

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    DAO to ADO

    I have a couple of questions dealing with the references. What is the difference between DAO and ADO? I have been reading that Microsoft is not going to be supporting DAO anymore. Does that mean they are just going to drop it or are they going to have some type of conversion process. Is there anyway to change a database from DAO to ADO?

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    Re: DAO to ADO

    DAO and ADO are both object models that can be used for accessing data and manipulating the data structures. DAO is oreinted towards Jet, while ADO is designed to work with various data sources including text files and even things like email databases and directories themselves. DAO is loaded with properties and methods for database objects, while ADO has a much simpler object model that is designed to be extended by the various OLE DB providers. If you have ever worked with class objects, ADO is more like a superclass with each of the providers implementing their own properties and methods to extend that class

    DAO is not going to be extended any further, but it will undoubtedly be backwards compatible for quite a while since there are some things that they haven't come up with an ADO equivalent for yet, and there are still plenty of DAO-based applications out there to maintain. Start learning ADO now, though, because you'll be using it for the web-based stuff that's just around the corner and it travels well between applications.
    Charlotte

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    Re: DAO to ADO

    What I can't understand is why, and this has happened on more than one machine, many VBA topics in the Help file for Access 2000 or Office 2000 relating to ADO don't work.
    In fact there are many more nonfunctional help topics for ADO than DAO! I'm sure they USED to work before I switched to Windows 2000. But now I just get "you need to re-install VBA help" messages which are incorrect. After I "re-install" nothing has altered at all.

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    Re: DAO to ADO

    Well, don't blame it on ADO. <img src=/S/grin.gif border=0 alt=grin width=15 height=15> HTML help is not quite ready for prime time in my opinion. A lot of times pressing F1 will get you error messages or (my favorite) a help screen that is completely empty but which may eventually populate if you go out for coffee meanwhile. However, if you can find the right magic words to type in the answer wizard, you'll go to the topic you were looking for. This isn't peculiar to Windows 2000 either. I run NT and see the behavior I described, in addition to obsure error messages that precede actually loading the help topic.
    Charlotte

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    Re: DAO to ADO

    This is what you call a delayed response, but, just in case you're still getting blank help pages or errors when you try and look up ADO information, here's how I fixed it:
    Copy the files
    msjro.chm and
    ado210.chm
    from the PfilesCommonSystemADO directory on your Office installation disk into
    Program FilesCommon FilesSystemADO (usually on C
    as documented by Microsoft. I then additionally had to open up the registry and add a string value to HKLMSOFTWAREMicrosoftWindowsHTML Help
    called
    ado210.chm
    and with a value of
    C:Program FilesCommon FilesSystemADO
    and now my help files function properly!
    It's apparently because Windows2000 comes with MDAC2.5 (which doesn't include these help files) so when you install O2k, which comes with MDAC2.1 (which does include the help files) the installer sees that a later version of MDAC is installed and doesn't bother installing any of its files.
    Hope that helps.
    Regards,
    Rory

    Microsoft MVP - Excel

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    Re: DAO to ADO

    However, it's simpler to download the 2.5 versions of MDAC_TYP.EXE from Microsoft's site and install it. It will take care of the situation without requiring any registry hacks.
    Charlotte

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    Re: DAO to ADO

    Thanks, Charlotte. I just wish I'd known that this morning! <img src=/S/doh.gif border=0 alt=doh width=15 height=15>
    Regards,
    Rory

    Microsoft MVP - Excel

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    Re: DAO to ADO

    My reply is slightly tardy too as I have just returned from a holiday in France wishing I were still there...
    Your reply is the only one that has hit the nail on the head! Yes it works and my first suspicion that it is Windows 2000 that messed up the HTML help of
    Office 2000 proves to be correct. Others kindly replied with surmises and general answers which weren't correct but your solution is apposite and right to the point! Thanks!
    The wonder is that so few have stumbled on this defect
    (it is an outright error) of Win2000 not installing the full Office 2000 help files. I personally find the Visual Basic help really useful in devising solutions and it was annoying me to have to leaf through textbooks to dredge up the answers. Now ADO (help) works fine.
    Moreover I have made a few changes to your ADO solution to come up with one that gets DAO 3.6 help working too (which also didn't function correctly).
    Copy the file DAO360.CHM from the Office installation disc found in this location:
    PfilesCommonMSSHAREDDAO
    to
    Program FilesCommon FilesMicrosoft SharedDAO
    (usually on C
    and edit the registry key dao360.chm
    (it was already there in my setup, otherwise create it)
    in
    HKLMSOFTWAREMicrosoftWindowsHTML Help
    ensuring the string value is
    C:Program FilesCommon FilesMicrosoft SharedDAO
    Reboot and BOB'S YOUR UNCLE!
    Now, are there are other sections apart from these two
    that don't work for similar reasons AND will the issue
    be all fixed up in OfficeXP?

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