Logical Data Model View and Physical Model View

[rneelakantan]

Does EA support Logical Data Model and Physical data model view?  For e.g., tools such as ERWin, CaseStudio, ERStudio, Q-Designer, Oracle Designer have an options to select Logical Model view and physical model view.  In logical model, i can define the relationship between two entities (customer and product) as "A customer buys many product" and "Product is purchased by many customers".  And in Physical Model view, I can actually go and define Primary Key, Foreign key, Indexes which are invisible in Logical View.  

Is this possible (toggling between physical and logical) in EA?

[«Midnight»]

I'm sure you'll get many replies, but I'll wade in and start it off.

AFAIK, you cannot do this in quite the way you would with the dedicated data modelling tools. However you may find the EA facilities more palatable depending on how you use modelling tools in your development environment.

What you can do is model the logical relationships as a class diagram. You can specify features (i.e. attributes, in the logical model) to the extent, and level of detail, required for your purposes. This might be at a very high level if you use the logical model primarily as an overview. It could be quite detailed, giving types etc. (either platform specific or independent) if you intend to directly evolve the logical model into the physical.

[You may find that chaning the connector end notation for the logical model diagrams will help you here. As of build 788 the non-UML notations appear to be working correctly.]

You can then create the physical model using the data modelling profile built into EA, or one of your own. Several of this forum's members have worked on EA transformation scripts to automate this process. You might want to search the forum for some helpful hints.

I've had some success using generic models at both levels. I have also created a CWM implementation using generic data types, which has been useful for building high-level data models at the conceptual and logical levels, before even deciding on the implementation platform(s).

A suggestion: you should pay very close attention to the language setting for each item in the logical model. If necessary create a generic language, either patterned after data types (generic or your chosen platform, as appropriate). Make sure the data types available (or that you use) are simple to understand, and can be mapped without distortion to your physical model.

[NB: If you are interested in using CWM, as of EA 6.1 you can load the OMG implementation directly from their XMI file. You will find it here: http://www.omg.org/docs/ad/01-02-03.txt.

Hope this gives you a starting place,
David

[Paolo F Cantoni]

[NB: If you are interested in using CWM, as of EA 6.1 you can load the OMG implementation directly from their XMI file. You will find it here: http://www.omg.org/docs/ad/01-02-03.txt.

Hope this gives you a starting place,
David

Hi David,
My .788 XMI Import failed with a
"Unknown XMI exporter or Version"
error.

Do I have to do anything special to import it?

Thanx,
Paolo

[AshK]

...My .788 XMI Import failed with a
"Unknown XMI exporter or Version"
error.

Do I have to do anything special to import it?...

Hey lads,

I found I was getting the same error; to import successfully I had to change the 5th line to:

<XMI.metamodel xmi.name='org.omg.mof.Model' xmi.version='1.3'/>

I'm not sure if this a problem with our importer, but i'll raise the issue with our MOF guy.

Ash

[Paolo F Cantoni]

Hey lads,

I found I was getting the same error; to import successfully I had to change the 5th line to:

<XMI.metamodel xmi.name='org.omg.mof.Model' xmi.version='1.3'/>
I'm not sure if this a problem with our importer, but i'll raise the issue with our MOF guy.

Ash

Thanks Ash,

Worked "Just like a bought one"...

Paolo

[«Midnight»]

Hi folks,

Sorry Paolo, I did not notice your reply until just now.

I first tried this with the first production build of EA 6.0, and had no problem. I just retried with build 788, and still had no warnings or other problems.

The CWM XMI file I have may be different than yours. I downloaded it from OMG some time ago. The third[/] line of mine reads:

<XMI xmi.version = '1.1' xmlns:Model='omg.org/mof.Model/1.3' timestamp = 'Mon May 06 16:42:16 2002' >

The ninth[/] line (without modification) reads:

<XMI.metamodel xmi.name = 'org.omg.mof.Model' xmi.version = '1.3'/>

My XML settings are pretty 'plain vanilla' but I do use the DTD in both directions.

David