Hi,
We use Corvu to report out of the MIMS database and it comes pre-configured with a MIMS knowledge library KL.

It is sometimes required to customise the KL in order to provide for joins, etc. However when we upgrade MIMS a new KL is delivered with MIMS and we loose all our customisations.

Any effectiuve strategies to handle this problem?

When we upgraded MIMS from 3013S to 4013, Mincom provided conversion programs I think dctmrg32.EXE and some others.
It merged the old KL with the new KL.
We could then upgrade all the queries and reports against the merged KL

The queries converted quite well - over 90% success rate.
The knowledge library ended up corrupted so we got rid of the merged one and went to the vanilla 4312 KL.
Converted queries continued to work - even in design mode.

Martin,
Thanks for the insight. I would like to understand how, as you changed KL twice, queries still open in design mode. The problem I had here was that as KL was changed, existing queries can still be executed, however when opened for Modify, the "Generate query" window is displayed with a blank list of fields and Edit SQL does not return the SQL for the query; therefore the query can no longer be modified and we cannot even get a hint about its original design. Therefore our investment in design appears to be lost.   
Maybe the questions I need to ask you are:
-did your 3.13 KL have customisations, such as virtual databases, tables & fields-with queries based on such custom items?
-was the Merge program able to handle the customised KL and merge the customisations in the resulting KL?
-were you able to diagnose why 10% of your queries did not convert? what was the effect on those and what did you do about them?

Our queries were still able to open in design mode because we used the converter.
We did have some customisations although not extensive.
However, the difference between 3013 and 4312 is enormous. 3013 KL was based on the MIMS tables (msf) where 4312 was based on views (msv).
The dict merge brought our customisations into the new KL. However, due to the complexity of the changes from 3013 to 4312, some of the queries based on the customisations and even some standard 3013KL did not work. That is they did not run - you could however still open in design mode so long as it is using the merged KL.
The queries which failed were re-written but this was made easier because they were able to be opened in design mode.
What versions of corvu and mims are you using?

Martin,

Thanks for the reply. We are running MIMS 4.1.01 and CorVu 4.10.55. Corvu is mainly used as an ad-hoc querying tool; application design did not really take off due to problems with administering the KL.

Our current KL has original MIMS tables msfxxx as well as a set of virtual tables msvxxx.    

It is great to learn about your experience as here we also have a MIMS upgrade in the pipeline. It has not yet been decided when and to which version of MIMS.

Calator,

Just a note if you are not already aware, there is a CorVu user guide "Knowledge Library and Directory Utilities" available from CorVu Support. This includes instructions for merging KL's, renaming databases and converting files etc.

Calator,
The reason you see a blank edit query dialog box is due to changes in the Knowledge Library. The Knowledge Library no longer contains the same fields or tables when you wrote the query. The sql will update when you edit the query and select Preview or Modify. Since the Knowledge Library was a new version from MIMSVul, you will need to use the dict merge utility to merge your old Knowledge Library to your new one as recommended by MGHarris.