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From "Robert Huber @ 7r" <roberthu...@sunrise.ch>
Subject Re: [ann] Apache Cayenne 3.1 goes beta
Date Tue, 09 Apr 2013 16:23:28 GMT
Hello Andrus

Thanks a lot for the new release 3B2 which was the reason to try Cayenne Modeler again.
We currently use EOModeler for all of our modelling tasks. Having tried Cayenne Modeler only
a little bit several times, I started seriously again with this build and your getting started
guide an built the Artist - Gallery project to see if Cayenne Modeler could now be a successor
for EOModeler.
But I assume I have some general understanding problems.

I would very much appreciate if you could demystify some of them. Thank you a lot for your
answers or hints in advance.

Task
– In EOModeler, the task is to model an ER-Model. For example, I create an entity, add attributes
and relationships between entities. I then can add column names and other implementation details
as column width, type, … So I make in one place the ER-Model and the mapping to the relational
model.
– In Cayenne Modeler, it seems, one has to start with the implementation side, i. e. the
relational model side, and then somehow create the ER-Model? So one is not exactly starting
with modeling, but wit the implementation?

Some Observations/Questions
→ Is this the intended procedure? Why doesn't it start on the modelling side, i. e. the
defining of entities (classes) with their attributes etc.? And then allowing to map it to
the relational model.

→ The splitting between the tables and classes seems quite complicate to me, especially
with the create ObjEntity and syncing between the two «models». May be there is a reason
for this separation and syncing which I don't recognize?

→ When creating an ObjEntity from an DBEntity (table), the name of the ObjEntity is in plural,
whereas a common naming is singular for the entity, e. g. Artist (as it is a set), and plural
for the table, e. g. artists. Unfortunatly (for me), the ObjEntity is also plural. I found
it can be overridden, but if one presses the green C button again, an new ObjEntity in plural
is created beside the existing in singular.

→ The primary key attributes are not displayed in the ObjEntity. Why not? It is displayed
in the 

→ The column name exists in ObjEntity as DbAttribute, and in the DbEntity (table) as column
name, i. e. it is in two places, but can only be edited in the DbEntity, not in the ObjEntity

→ Naming in Cayenne Modeler its very strange for me, as many things seem mixed. For the
ERM side (P.P.S. Cheng) I would have expected terms like entity, attribute, relationship,
sub type, super type, … and for the relational model (F. Codd) I would have expected terms
like table (relation), column, domain, … 

→ If I organize the ER Diagram and Class graphs as I like, it is set to some default (even
depending on the window size) after reopening the project. If I organize the ER Diagram, it
should absolutely keep it's layout. I think this is a necessity for larger models.

→ I miss the ability to place some sort of text box in the ER Diagram and to give a self
defined color to the entity (class) or table.

→ I did not find EOPrototypes, a great concept for applying DB types for quickly porting
a model to a new database. I really have problems if this is not available.

As I would primarily use the Cayenne Modeler (as we work with Servoy, we will not use the
Cayenne Framework), I am at the moment not comfortable to make the switch from EOModeler to
Cayenne Modeler. I am very much aware that making such a tool is a lot of work and appreciate
it in every way. So the above points are not meant as a critic but a way to find out if Cayenne
Modeler could be a successor tool for us. I am also a bit unsure for what tasks exactly Cayenne
Modeler is really meant?

Thanks and best regards, Robert



_/ _/ _/ _/ _/                             r. huber
               _/
            _/      _/      _/           7r gmbh
         _/      _/  _/               alpenstrasse 93
      _/      _//                   ch-8200 schaffhausen
   _/      _/
_/      _/                    tel. +41 52 624 81 15   www.seven-r.ch



On 12.06.2012, at 13:17, Andrus Adamchik wrote:

> Very happy to announce Cayenne 3.1 beta! The full announcement can be found here:
> 
> http://cayenne.apache.org/2012/06/12/cayenne-31-beta-released.html
> 
> Download is here of course:
> 
> http://cayenne.apache.org/download.html
> 
> A note on 3.1 documentation. The new PDF guides shipped with the download document all
the new features, and some of the old ones. However they are still work in progress. I suggest
still checking the PDFs, as they are the only source of information on the DI, configuration
properties and the new way to start Cayenne runtime, but go back to 3.0 HTML docs whenever
you find a gaping hole in the PDF:
> 
> http://cayenne.apache.org/doc30/overview.html
> 
> We should finish the docs by the time 3.1 is final.
> 
> Cheers,
> Andrus


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