Aha ok, Im correcting all the naming errors.

I still don't get it about the PersonXConvetion - Person and Convention tables.


On Mar 21, 2008, at 11:26 PM, Guido Neitzer wrote:

On 21.03.2008, at 19:39, Gustavo Pizano wrote:

in PersonXconvoc I have those attributes as pk, so a Person can be in different convocations just once.

If you have more than just a plain join table with two keys, I would always have a separate pk for that table and the two others would just be foreign keys. You still model a m:n relationship with that, it can have properties.

if I do that,  i understand you mean something like this, no?

<<inline: Picture 1.png>>



if that's so. then I can have the following data.
id      id_person       id_convocation

1               01                      1
2               01                      1

which its not accepted because a person can't be twice in the same convocation.

Im checking the relationship of this 2 tables and don't see the m:n , im gonna make the relationships again and take care about that relationship.

As JVF said "You will have to model the middle table as an entity by itself, so give it a meaningful name (?Assignment?Meeting? Appointment?). You will end up with Person <-->> ?Appointment? <<--> Convocation."
 I know that, but I though that middle table was PersonXConvocation.

Im not getting it there... :(

Gus

PS I changed the study_level_id to id_study_level already, just that its not reflected on the picture.




It is not strictly necessary to do this, but your life will be miserable in EOF if you don't create a seperate pk there.

And to be consistent you should make the attribute "id_study_level", then you are consistent with your other foreign keys.

cug


--
http://www.event-s.net


 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list      ([email protected])
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com

This email sent to [EMAIL PROTECTED]

Reply via email to