Can MDAC 2.5 install over 2.6 or higher?

  • Thread starter Thread starter candc
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candc

I'm aware of some MSI's that contain the MDAC 2.5 merge module. I
just wanted to confirm that if one attempts to install MDAC 2.5 on a
W2K (or WXP) machine that has MDAC 2.6 or higher, that the OS would
prevent such a thing from happening. I tried to install MDAC 2.5
manually (from Microsoft's site) on a W2K PC that had MDAC 2.7 and I
got an error message saying that MDAC 2.5 was already installed on the
PC. Also, I figured that even if the install was allowed to proceed
using an MSI, that Windows Installer rules would prevent the older
files from overwriting the newer ones on the PC.

I have an application that other people developed that attempted to
install MDAC 2.5. I just want to make sure that it 1) it would not
have installed anyway and 2) any key functionality the developer used
in MDAC 2.5 would be upwardly compatible in 2.7.

Thanks in advance for anybody's opinion.
 
The MDAC merge modules don't actually install MDAC (aunless something has
changed recently). Read this article below:

http://msdn.microsoft.com/library/d...coninstallerpackagefilesmergepackagefiles.asp

where it says:
Quote
Note Unlike all other merge modules Visual Studio Installer provides, the
mdac.msm file does not install Microsoft Data Access Components when the
installer package it belongs to is run. Instead, mdac.msm simply checks for the
presence of Microsoft Data Access Components on the target machine.

The real issue is what happens when you run mdac_typ.exe, and I think that
message you saw is normal and an old one shouldn't replace a new one. In any
case, a reasonable program should check Version in HKLM\Software\
Microsoft\DataAccess before doing an install.
 
There are some MSDC merge modules out there that actually install MDAC. But
they do this by calling mdac_typ.exe in a custom action, so they are simply
wrappers around Microsoft's MDAC package. I assume/hope that older MDAC
packages would not downgrade MDAC. You already tested this with MDAC 2.5.

--
Stefan Krueger
Microsoft Windows Installer MVP

Please post your questions in the newsgroup or vist one of these web sites:

Windows Installer FAQ
http://www.msifaq.com - http://www.msifaq.de

InstallSite - Resources for Setup Developers
http://www.installsite.org
http://www.installsite.de (GERMAN)


Phil Wilson said:
The MDAC merge modules don't actually install MDAC (aunless something has
changed recently). Read this article below:

http://msdn.microsoft.com/library/d...coninstallerpackagefilesmergepackagefiles.asp

where it says:
Quote
Note Unlike all other merge modules Visual Studio Installer provides, the
mdac.msm file does not install Microsoft Data Access Components when the
installer package it belongs to is run. Instead, mdac.msm simply checks for the
presence of Microsoft Data Access Components on the target machine.

The real issue is what happens when you run mdac_typ.exe, and I think that
message you saw is normal and an old one shouldn't replace a new one. In any
case, a reasonable program should check Version in HKLM\Software\
Microsoft\DataAccess before doing an install.
--
Phil Wilson [MVP Windows Installer]
----
candc said:
I'm aware of some MSI's that contain the MDAC 2.5 merge module. I
just wanted to confirm that if one attempts to install MDAC 2.5 on a
W2K (or WXP) machine that has MDAC 2.6 or higher, that the OS would
prevent such a thing from happening. I tried to install MDAC 2.5
manually (from Microsoft's site) on a W2K PC that had MDAC 2.7 and I
got an error message saying that MDAC 2.5 was already installed on the
PC. Also, I figured that even if the install was allowed to proceed
using an MSI, that Windows Installer rules would prevent the older
files from overwriting the newer ones on the PC.

I have an application that other people developed that attempted to
install MDAC 2.5. I just want to make sure that it 1) it would not
have installed anyway and 2) any key functionality the developer used
in MDAC 2.5 would be upwardly compatible in 2.7.

Thanks in advance for anybody's opinion.
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