Question

For the moments bars represents a String with all the Bar ids with ‘;’ separator

like 6;5;9;15

class Foo(db.Model):
    id = db.StringProperty(multiline=True)
    name = db.StringProperty(multiline=True)   
    bars = db.TextProperty()

class Bar(db.Model):
    id = db.StringProperty(multiline=True)
    name = db.StringProperty(multiline=True)

What must I do to explicit Foo contains some bars in db?
And also how is going to look my :

f = Foo()
f.name= 'aName'
f.id = '3615'
f.bars = '6;5;9;15'
f.put()

Answer 1

For a start, you never want to store multiple values inside a single textfield. AppEngine’s datastore supports multi-valued properties (such as ListProperty): you should use those.

That said, there’s no multi-valued equivalent of ReferenceProperty built in. This article on the AppEngine documentation site gives a good example of how to model a list of keys.