class Student(db.Model):
teacher = db.ReferenceProperty(Teacher, collection_name='students')
name = db.StringProperty(required=True)
zip_code = db.IntegerProperty(required=True)
square_footage = db.IntegerProperty(required=True)
month_entries = db.IntegerProperty(required=True)
class Bill(db.Model):
student = db.ReferenceProperty(Student, collection_name='bills')
bill_month = db.DateProperty(required=True)
energy = db.IntegerProperty(required=True)
从上面显示的模型设置中......我可以使用以下方式轻松显示所有存储的账单:
bill = models.Bill.all()
for stubs in bill:
print stubs.energy
print stubs.student.name
但是我如何列出每个学生的账单?在 SQL 中,我会这样说:
SELECT * FROM Bill WHERE Student.Name = Samuel
我想我不明白如何检索 ReferenceProperty 给出的账单。在 GQL 中似乎并不那么简单。如何按参考属性查询?