Re: Mapping objects into rdb

Johan Nilsson schrieb:
>
> Hi,
>
> I'm designing a system where the objects' data need to be persistently
> stored in a rdb (Oracle8). For compatibility reasons with existing
> systems,
> I cannot use an odb. I'm doing the development in C++ and likely
> COM/DCOM.
> [...]
> If you have any experience in designing and implementing a similar
> system,
> please share it with me.

Well, I have been working at a project where they had done something similar. They did it by storing the objects in blobs. Other approaches try to store objects in tables so you can see every attribute. The second solution has the advantage and disadvantage that you can modify objects without their control. The first solution is slightly better for templates.

The main problem is the often called "impedance mismatch" between OO concepts and relational concepts. This brings you always into trouble: Either your mapping is quite generic and slow or it is optimized, fast and thus difficult to amend. However there are products on the market. Unfortunately I have no pointers for you.

In any case: It's an awful topic because OO and relational db's simply do not fit. And maybe the effort is better spend on convincing people to use an object oriented database. For masses of data I recommend a page server which is more efficient in this case.

Bye

        robert

-- 
Robert Klemme
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