Hi,
I'm going to develop a Preventive Maintenance application. It's really a dynamic systems that have a base component: SERVICE
There is a same procedure apply on different services (schedule program) but it's difficult to define dynamic services by users because each service has its own features.
I'm looking for a way to model my database that support service definition by users. I can't model it through Relational DBs. Is there anyway to store data more flexible than relational DBs?
Exactly, I'm looking for new technologies that support dynamic and flexible situation for this problem.
Can anybody help me?

yes, there is

do a search for EAV (entity-attribute-value)

Dear Consultant,
It's OK but I'm looking for a polished, stable product to conduct my project. I can't find such instance of EAV.
Is there any database engine based on EAV that I can utilize it in my project?

Test files work pretty well for this kind of storage. MUMPS and LISP are pretty flexible too. As long as you can deal with the performance of highly flexible systems, there are many ways to get almost unlimited flexibility.

The Microsoft Windows Registry is a great example of EAV storage. I don't beleive that there are any commerically viable database products that are based on EAV.

-PatP

but if needs be you can fake EAV using a relational database.

I would recommend you look into the Raima RDM Embedded system, which is built off of the network database model, using member/owner sets. The product has been proven and is widely used in many areas, and can give you the flexibility you're specifically looking for. There's a free SDK you can look at to see if it works for you or not.

Here's some info on the network model:

http://en.wikipedia.org/wiki/Network_model
http://www.raima.com/docs/rdme/9_1/C...Database_Model


And on RDM Embedded:
http://www.raima.com/products/rdm-embedded/

Hope this helps.

_________________________________
Embedded database systems | raima.com

If you're unable to get the performance you need when modeling your data in a relational DB, you might consider an in-memory embedded database.

One example is the eXtremeDB embedded database:
http://www.mcobject.com/extremedbfamily.shtml

eXtremeDB also supports a wide variety of DB indexes - not just B-trees but also R-trees, KD-trees, Patricia tries and hash - which can be helpful, depending on what kind of application data you are managing.

FPGA