Hello!
I'm just wondering if there's an easy way (maybe a property) to determine if my installation is an upgrade to a currently installed older version or not.
The Setup performs some custom actions on installation which should not be executed if the product is already installed and will be updated by the Setup.
TIA,
Jan.
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Determine upgrade...
Started by
hilbe
, Aug 06 2002 14:02
1 reply to this topic
hambone
-
- Members
- 206 posts
Posted 07 August 2002 - 19:37
i might be wrong on this but, due to the nature of the way msi works upgrades and patches are typically performed by patching the admin. install of an application and then un-installind and re-installing the product.
if you were to attempt to upgrade an exisiting installed msi you would have to modify the two major areas of the product. one area is the application code are and the other is the msi control info. the application code consists of the registry entries and files associated with the actual application. this area is relatively easy to change but when msi checks the system it will see the application as 'broken' and attemp a repair. the other area being the msi control info. consists of the msi registry database and the locally stored 'cached' msi files. this area is more difficult to modify.
as i mentioned with the upgrading and patching that occurs i believe you are limited to removing the old stuff and then installing the new...
one of the reasons for this is the extensive use of GUIDs in the msi world and the need to ascertain that they are indeed globally unique. as such a unique product should look the same on all systems whether it was 'upgraded' or 'net-new' installed...
if you were to attempt to upgrade an exisiting installed msi you would have to modify the two major areas of the product. one area is the application code are and the other is the msi control info. the application code consists of the registry entries and files associated with the actual application. this area is relatively easy to change but when msi checks the system it will see the application as 'broken' and attemp a repair. the other area being the msi control info. consists of the msi registry database and the locally stored 'cached' msi files. this area is more difficult to modify.
as i mentioned with the upgrading and patching that occurs i believe you are limited to removing the old stuff and then installing the new...
one of the reasons for this is the extensive use of GUIDs in the msi world and the need to ascertain that they are indeed globally unique. as such a unique product should look the same on all systems whether it was 'upgraded' or 'net-new' installed...