Re: Entity vs. Table
Date: Tue, 15 Jun 2004 16:31:43 GMT
Whan an SME is?
I completely disagree. You can communicate a lot more precisely with a
relational design because it is a lot more expressive. ERD is a toy
>with the scenarios Dawn outlines about subject matter experts becoming
>learning enough IT to implement what they want in Pick, the salient point
>is NOT the difference in data models. It's the difference in how the gap
>between subject matter expertise and IT expertise gets bridged.
It is a lot easier to teach The Relational Model to the subject experts, and they will be able to implement or to check what they want with a little fraction of the effort needed if they used the archaic and primitive Pick.
And ERD does not help for this. The IT expert will think that he
understands the problem but he only understands a part.
The subject matter experts don't know ERD, but most of them already
know predicate logic and set theory. I prefer to teach them The
Relational Model than ERD. With ERD most rules will not be captured
causing a lot of communication problems.
The subject matter experts don't know ERD, but most of them already know predicate logic and set theory. I prefer to teach them The Relational Model than ERD. With ERD most rules will not be captured causing a lot of communication problems.
> In cases where the subject matter is
>easily learned, the IT expert can proceed directly to design without cross
>checking analysis. Maybe in these cases, an ERD is superfluous.
>In cases where the IT expertise is easily learned, the SME can learn what's
>needed, and implement the right thing.
> Maybe these cases are where Pick,
>and products like it, do their best.
No, Pick is a very limited archaic toy. Here is where The Relational Model does their best.
>In cases where neither the subject matter nor the required technology are
>easily learned, and no one knows both of them a priori, it gets
>interesting. This is where we start to play volleyball.
ERD promotes volleyball because the subject matter expert can not communicate the requirements to the IT expert and the IT expert can not know the subject matter with detail. This leads to a long and painful iterative process.
Regards Received on Tue Jun 15 2004 - 18:31:43 CEST