[Zope] [ADVANCED] How do YOU guys do many-to-many in Zope without relational?

Michel Vayssade michel.vayssade@utc.fr
Tue, 23 Oct 2001 10:13:28 +0200 (MET DST)


On Mon, 22 Oct 2001, Max M wrote:
> I basically have two zClassses. students and subjects. There can be many
> subjects, and in any subject there can be any number of students.
.......

in such a case I will do it that way :

each student_object will have a unique id, say "stu_01234"
each subject_object will have a unique id, say "suj_56789"

each student_object will have a list of subjects were he applied :
	['suj_56789','suj_567','suj_512',...]

if a subject is deleted
you can protect your code by :
	creating a global_subject_list (permanet or dynamic)
		global_subject_list.has_key[a_subject]
or you can write your own "delete_subject" fonction which will
remove from student lists the delete subject

the uniques ids act has an indirection allowing to modify the object
without breaking any link

....

--
  _/   _/ _/_/_/  _/_/ Michel.Vayssade@UTC.fr    Service Informatique
 _/   _/   _/  _/      T:33/0-3.44.23.49.24 Universite de Technologie
_/   _/   _/  _/       F:33/0-3.44.23.46.77 BP 20.529 60205 Compiegne
 _/_/    _/    _/_/    _ mv@utc.fr __/www.utc.fr/~vayssade____ France