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
