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Recursive relationship with Google App Engine and BigTable

In a classic relational database, I have the following table:

CREATE TABLE Person(
    Id int IDENTITY(1,1) NOT NULL PRIMARY KEY,
    MotherId int NOT NULL REFERENCES Person(Id),
    FatherId int NOT NULL REFERENCES Person(Id),
    FirstName nvarchar(255))

I am trying to convert this table to a Google App Engine table. My problem is with the fields MotherId and FatherId. I tried the code below, but no chance. Python says that it does not know the type of the Person object.

class Person(db.Model):
    mother = db.ReferenceProperty(Person)
    father = db.ReferenceProperty(Person)
    firstName = db.StringProperty()

Does anyone know how we can model recursive relationships in a Google App Engine spreadsheet? How can I get around App Engine restrictions?

UPDATE I want to expand the problem a bit ... What if I wanted to add a collection of children?

children = db.SelfReferenceProperty(collection_name='children_set')
dad.children.append(childrenOne)

I tried this and it does not work. Any idea what I'm doing wrong?

Thanks!

+5
1

, SelfReferenceProperty

class Person(db.Model):
    mother = db.SelfReferenceProperty(collection_name='mother_set')
    father = db.SelfReferenceProperty(collection_name='father_set')
    firstName = db.StringProperty()

.

+10

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