Re: Oracle and Visio

internetmaster <youlove_at_me.com> wrote in message news:<3D408094.7080505_at_me.com>...
> Daniel Morgan wrote:
> > internetmaster wrote:
> >
> >
> >>Daniel Morgan wrote:
> >>
> >>>Charles wrote:
> >>>
> >>>
> >>>
> >>>>On Tue, 23 Jul 2002 10:27:30 +0100, "Telemachus"
> >>>><telemachus_at_ulysseswillreturn.net> wrote:
> >>>>
> >>>>
> >>>>
> >>>>>Yes.
> >>>>>But only if all the pk and RI and fk constraints are in place otherwise it
> >>>>>can only get what it can see.
> >>>>>
> >>>>
> >>>>I just used Visio on a legacy database. 60 or so tables and no fk/pk
> >>>>defined. All you get is a set of tables, not all that well organized.
> >>>>Not very usefull although it is a place to start.
> >>>
> >>>
> >>>Why would anyone have a relational database without primary key constraints?
> >>>
> >>>Legacy, I presume, does not mean before normalization was defined.
> >>
> >>We have an application at work which I won't name but will reveal the
> >>vendor's name -- Computer Associate.
> >>
> >>We want to expose the underlying Oracle database to a reporting tool and
> >>we asked them to send over a data model so we could understsand how the
> >>tables relate to one another. They sent over a lovely data model.
> >>
> >>The other day, I went into ERWin and reverse engineered the database and
> >>found that it actually doesn't have any keys or RI. I plan on calling
> >>CA next week.
> >>
> >>
> >>>Daniel Morgan
> >>>
> >>
> >
> > I'm not surprised. A surprisingly large number of commercial products do 100%, or
> > virtually 100%, of their data integrity constraint through their front-end. And
> > the horrible quality of the data they contain bears witness to this fact.
> >
> > For me this is a show-stopper for two reasons:
> >
> > 1. All it takes is one person with an ODBC connection and every integrity rule is
> > violated.
> >
> > 2. To make any substantive changes to the product you must pay their consulting
> > division outrageous fees for even the most mundane changes.
> >
> > I consider a product built on top of a relational database with integrity
> > controlled by the front-end a no-sale. I have never recommended one for a client
> > ... and never will.
>
>
>
> Why do you think they do this? So they can port the application to
> different database systems ? I was surprised to uncover this reality
> about the application. And now you're telling me that this is common
> place ?!? That's an eye opener.
>
>
>
>
> >
> > Daniel Morgan
> >

Exactly: to port the application to different database systems, allowing for even the database system with the most minimal function set to work with the app.
A second reason would be: because they have no clue with respect to the differences between database products A third reason would be: to make their customers dependant of their consulting activities. Basically you can't maintain any data, and you need to hire the vendor to bring in expensive 'tools'.

Regards

Sybrand Bakker
Senior Oracle DBA Received on Fri Jul 26 2002 - 11:58:12 CEST