Re: Migrating from Hierarchial DB model to RDBMS OR ?

On Friday, April 29, 2016 at 9:02:30 AM UTC+10, Giri Reknar wrote:
>
> 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 ?

First, it is no problem at all to convert an Hierarchical data model to a Relational data model. In fact, if the database is truly hierarchical, it will be streets ahead of 95% of the Relational databases that have been implemented. The Relational Model is founded on the Hierarchical paradigm (I won't say it is a model), it is a progression of it. It has the central features of the Network model as well. Obviously much more than the Hierarchical paradigm, it has a complete theoretical basis.

(Further detail can be found in my thread re Hierarchical Model and its Relevance in the Relational Model"

Second, you do have to understand:

• data: the organisation and Normalisation of /any/ data
• data: the content (if you don't understand your data, you can't Normalise it properly)
• the Relational Model (the real thing, the Dr E F Codd paper, not the freaky garbage that is taught these days as "relational".  Plus everything that the high-end platform suppliers have implemented)

Third, if you use a genuine SQL platform, it is straight forward. There is of course a bunch of freeware/vapourware/beware out there that is:

a.  not SQL (they use the name of the standard fraudulently)
b.  has many special-needs features (perfect for special-needs people) but lack the basics, eg. compliance  and ACID Transactions
c.  has no Server Architecture, performs like a three-legged dog (contention; duplication; hardware required)
d.  you will have to rewrite your "sql" code when you port the database to a real platform.

> Please note XML is Hierarchial as well but not sure how different it is from IMS

XML is not hierarchical, and it is not a form of data model either. It cannot be compared with IMS or Sybase or MSSQL.

It is an implementation method. Sure, the semantics and syntax are hierarchical, but if one is not aware of the hierarchies in the data; if one has not modelled the data according to the Hierarchical paradigm or the Relational Model, then, the implementation and the data will not be hierarchical.

Cheers
Derek Received on Tue May 17 2016 - 07:45:28 CEST