>Yes I have experience using E-A-V in VFP although we are using SQL Server for the data store but it doesn;t make that much difference. What is giving you problems?

Hi!
I faced with what I found common problems of this approach.
First is slower data retrieval. Ok, I can cache all data using some class (collection of entities each of them is collection of attributes). This way data access if very fast while read data to cahce and dump cache to disk seems to run in seconds even with thousands of entities.

Second problem is that there are no available mechanisms (IMHO at least for VFP) to query EAV data, to validate it, to protect uniqueness, reference integrity, etc. Creating such mechanisms looks like crating new DBMS from scratch. Googling on this topic I found that meny developers tried EAV but abadoned it because of this problems.

In fact, I need a to create a data storage for system which must allow continious development which forces frequent changes to data schemes and even more - dynamic definition of some data schemes based on configuration data.
So, I'm still in question to continue developing EAV engine for VFP or to choose another concept.