Re: Data Mapping in Designer/ 2000

Designer/2000 doesn't handle this particularly well.

Assuming you create an ER Model as the "logical model", and use Table Definitions and Column Definitions as the "physical"...

1. The repository only supports 1:M from attribute to column, e.g. Each Column may implement one and only one attribute. This is very frequently not true when trying to map a physical system back to a normalized ER Model.
2. Sharing an entity also carries with it the sharing of any tables that are mapped to this entity. This can lead to naming clashes. As an example, if you have an entity EMPLOYEE and map that to a table called EMP in application A, you won't be able to map it to a table called EMP in application B.

So it depends on how complete/accurate you need to be.

[Quoted] An alternate solution is to create an ER model, and possibly physical models, but instead of using the built-in associations, create your own "association" tables using the meta-model view of entity, attributes, columns, tables, etc. Jim Smith <jim_at_jimsmith.demon.co.uk> wrote:

>We have a problem of reconciling multiple data structures and are
>considering using Designer/2000 to help us. Does any one have any
>experience of doing something similar?
>
>THe situation is that we need to build interfaces between several
>completely different systems which contain much the same data and we
>would like to document the data mapping. I imagine we would have one
>logical attribute (eg trade_date date) and a number of physical
>attributes with a name and a format (eg TRDDAT INTEGER (Julian date),
>trade_date float (1904 based offset). There are complications in that
>in some cases the mapping is not one to one between systems.
>
>We would like to be able to store the information and produce a report
>with a format something like this.
>
>Logical System1 System2 SystemN
>
>Name Log.Type Name(s) Phys Type etc
> Derivation
>
>I have a half thought-out scheme which goes something like this.
>
>Create an application for each system and for the logical model.
>Create a logical model and share it with the others.
>Derive tables from the shared entities and modify the table formats and
>descriptions to match the physical structure of the other systems.
>OR
>Retrofit tables into the applications and then somehow link those the
>the entities shared from the other application.
>
>
>Is this feasible, or is there a better way?
>
>TIA
>--
>Jim Smith

-JJ

 Jeffrey Jacobs & Associates
 Oracle Designer/2000 Consulting & Training  951-2 Old County Road, Suite 119, Belmont, CA 94002  Voice: 415-571-7092, FAX: 800-665-1379 CompuServe: 76702,456  Internet: jmjacobs_at_ix.netcom.com     Received on Mon Feb 24 1997 - 00:00:00 CET