Re: Updatable views

"Rick Elbers" <rick.elbers_at_chello.nl> wrote in message news:3189p1dlv9qpofqai5nq8v32keao7amiph_at_4ax.com...
> Dear database experts,

> Can somebody enumerate the problems with an updatable view for me ?
> With an updatebleview:= joined set of related tables and relations
> from which rows can be updated, inserted and deleted like you
> can in a simple table or master-detail relation.

What is an updatable view in your view ? What do you mean by joined set of related tables and relations ? Maybe you mean just a set of tables ?
What do you mean by related ?
There is any constraint definition ?
Who is enforcing the constraints ? The DBMS or the application ? Who is doing the translation of the update requests ? The application or the DBMS ?
How you deal with the errors ?
Are we talking about SQL DBMS or something else ? etc. etc. etc.

> My first try is to find hierarchy in de database by finding the
> absolute parents assigning them level 0. Parents of my table are
> considered those relations in which my foreign key doesnt allow
> DBNull.

What if do not find any parent this way ? And what is the purpose of building the hierarchy ?

> Then from there on proceed to give every table that has no parents but
> level 0 parents a level 1 etc.
>
> Problems seem to be autojoins and multiple relations between tables.
> Those problem can be solved to use every table only once in the scan.
>
> So the first question is: will this way of hierarchising the
> relational db always valid ?

> Then secondly given the hierarchy what problems remain when we talk
> about insert/update/delete and all kinds of combinations of those ?

Gee! Let me think. The problems are ... what is the problem again ?

> Regards and tx for answering,
>
> Rick Elbers
>
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>
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Received on Wed Dec 07 2005 - 10:08:57 CET