id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
17253	Add foreign object in memory without saving to database	cyberkoa@…	nobody	"Similar to the following post
http://stackoverflow.com/questions/7908349/django-making-relationships-in-memory-without-saving-to-db?answertab=active#tab-top


class Group:
   name = models.Chars()


   def save():
       super(self, Group).save()
       # access foreign objects
       members = self.groupmember_set.all()
       
      

class GroupMember:
   group = models.ForeignKey(Group)
   member = modesl.ForeignKey(User)


I have a page to allow people to create Group , and invited existing user to become member.

When form is submitted, Group data and GroupMember data is submitted together. 


I would like to override the Group's save function() , and in the save function(), I need to access the GroupMember data.

Example code

g = Group(name='abc')
gm1 = GroupMember(member=user1, group=g)
gm2 = GroupMember(member=user2, group=g)

g.groupmember_set.add(gm1)   # Add to memory , I do not want to save to db immediately
g.groupmember_set.add(gm2)   # Add to memory , I do not want to save to db immediately
g.save()
gm1.save()
gm2.save()

Since the .add() function save the related object to db immediately , causing error. 

I do not want to save the Group object first , because it will trigger 2 times save() 









 "	New feature	new	Database layer (models, ORM)	1.3	Normal				Unreviewed	0	0	0	0	0	0