Re: Migrating from Hierarchial DB model to RDBMS OR ?

On Friday, April 29, 2016 at 1:02:30 AM UTC+2, Giri Reknar wrote:
> Hi
>
> I am working IMS DB, a Hierarchial data model and need to convert it to a MODEL where I can build a Web app, I am thinking RDBMS unless there is something else is suggested.
>
> Now How do I go about Hierarchial to Relational ?
>
> Please note XML is Hierarchial as well but not sure how different it is from IMS

I would like to mention that this post is one of the most serious issues and problems in DB theory. This topic has the following name: Mapping one data model into another data model.
Related to this problem, I gave my solution for this problem. Roughly speaking my solution consists of the following: these data models should be presented with corresponding atomic structures. When we have atomic structures of these two data models, then it is easy to construct the mapping between these atomic structures. My solution assumes that the corresponding conceptual model is solved also by using atomic structures. My solution can be found on my website http://www.dbdesign11.com

As far as I know this is the only complete solution to the problem of the mapping between two data models. In case you are interested in my solution, feel free to ask me that what you are interested, I will try to answer.

Notice also, that other solutions that use two data models are wrong and therefore illegal. Here I think primarily on mapping from some data model into relational model. Also mapping from ER model into relational model is illegal. For example, Codd introduced "entity type" to make a "bridge" between ER model and the relational model. Of course "entity type" does not solve the mapping between two data models, at all. C. Date also uses this "technique" by applying "entity type".

Vladimir Odrljin Received on Mon May 16 2016 - 22:17:05 CEST