Re: [Modeling-users] What for?

[Sebastien B. <sbi...@us...>]

        Hi,

  ...And sorry for the late answer

Luciano Andrade <and...@ya...> wrote:
> I whant to know what meens the attributeUseForLooking,

The 'usedForLocking' property is not used yet --it will be used to
indicate which attributes should be monitored when the forthcoming
optimistic locking feature is implemented.

>  what mees that a relation is a classpropety, what if
> a propiety is not a classpropety,=20

The 'classProperty' flag indicates whether the related attribute is part
of the class' attributes. For example, 'firstName' is a class property
in entity Person: any object of class Person has a property 'firstName';
on the contrary, the primary key is not a class property, it is just a
column in the database that is not exposed at the object level (so in
this case the DB's table has a 'id' column but class Person does not
have any 'id' attribute)

> what the join's semantics meens,

This has to do with different sets of objects returned by a SQL query
--I myself only use inner joins (ie themost natural one, at least for
me;), so instead of trying to explain things I do not master at all, I
prefer to give you some links that ill do the job better then I could:


  Getting the Right Data with SQL Joins:
    http://www.devx.com/dbzone/Article/17403/0/page/1
=20=20
  Fropm postgresql:
  http://www.postgresql.org/docs/7.4/interactive/tutorial-join.html
=20=20
  O'Reilly:
    (pointed to by: http://www.onlamp.com/pub/ct/19)
=20=20
    http://www.onlamp.com/pub/a/onlamp/2001/05/24/aboutSQL.html
    http://www.onlamp.com/pub/a/onlamp/2001/06/01/aboutSQL.html
    http://www.onlamp.com/pub/a/onlamp/2001/06/15/aboutSQL.html
    http://www.onlamp.com/pub/a/onlamp/2001/06/27/aboutSQL.html

> what about circular relations, can the module handled.


  Not sure what you mean: do you mean reflexive relationships,
  i.e. where the source and destination entities are the same entity?
  If this is the case, have a look at the sample model in the User's
  Guide:

     http://modeling.sourceforge.net/UserGuide/model-author-books.html

  It has a reflexive relationship Writer-->Writer (it is a directional
  relationship, but you can have a one-to-many bi-directional
  relationship as easily), which is modeled exactly the same than
  "standard" relationships. The corresponding PyModel is exposed here:

     http://modeling.sourceforge.net/UserGuide/pymodel-sample.html


Should you have other questions, feel free to ask for more here!


-- S=E9bastien.