经过大量的研究，对我来说很多阅读here在某些情况下仍然不清楚父母和孩子是如何工作的：
+------------------------+ +------------------------+
| Room Model | +----------------+ | Room Model |
| <-----------+ +-------> |
+--+----------------+----+ | Supporter | +------------------------+
| | +----------------+ | |
| +------v-----+ | +------v-----+
| | | | | |
| | customer | | | customer |
| | | | | |
| +--+---------+ | +--+---------+
| | | |
| | | |
+--v+-----------v-+ +--v+-----------v-+
| | | |
| Device | | Device |
| | | |
+---+-----------+-+ +---+-----------+-+
| | | |
| | | |
| +-----v------------+ | +-----v------------+
| | | | | |
| | Issues / tickets | | | Issues / tickets |
| +------------------+ | +------------------+
| |
+v---------------+ +--------+ +v---------------+ +--------+
| pdf / pics | |Blob_key| | pdf / pics | |Blob_key|
| | | | | | | |
+----------------+-->--------+ +----------------+-->--------+
以下是我的情况：
我有不同的房间和房间，模型是关系中最高的实体，它不会改变，但所有与之相关的孩子都会改变，其中一些孩子会有更多的孩子。因此，一个房间可以同时有几个顾客和几个设备，其中一些属于房间，一些设备分配给房间：
class Room(MainModel):
# room_number is ID or key of room which is the parent of all entities
room_number = ndb.StringProperty()
# I don't know if this is the correct way to do this.
devices = ndb.KeyProperty(kind='Device', repeated=True)
# maybe this should be in the Device model?
devices_allocated = ndb.KeyProperty(kind='Device.allocation', repeated=True)
based_supporters = ndb.KeyProperty(kind='Supporter')
supporter = ndb.KeyProperty(kind='Supporter')
customers = ndb.KeyProperty(kind='Customers', repeated="True")
# Or should I go for ndb.KeyProperty(kind='Issue', repeated="True")?
issues = ndb.KeyProperty(kind='Vehicle.issues', repeated="True")
然后我有支持者照顾房间内容（客户和设备），他们可以支持超过1个房间，因此有几个客户和设备（房间的孩子），并有一个基地房间，意味着他们坐着在监控其他房间的房间里......
class Supporter(MainModel):
# id is ID or key of supporter which is child of room but becomes child of another room if changed
id = ndb.StringProperty()
name = ndb.StringProperty()
#I wonder if is possible to get these entities from the room model... Like this
devices = ndb.KeyProperty(kind='Room.devices', repeated=True)
customers = ndb.KeyProperty(kind='Customer', repeated=True)
#room which supporter stays
base_room = ndb.KeyProperty(kind='Room')
#rooms which supporter supports
rooms = ndb.KeyProperty(kind='Room', repeated="True")
然后我有客户，他们在一个房间（父母），可以使用一个设备（房间的孩子）应该可以根据情况更换，客户可以更换房间，因此房间的设备：
class Customer(MainModel):
# id is ID or key of customer which is child of room but becomes child of another room if changed
id = ndb.StringProperty()
name = ndb.StringProperty()
# device customer is using which can change
device = ndb.KeyProperty(kind='Device')
supporter = ndb.KeyProperty(kind='Supporter')
#customer room which can change
room = ndb.KeyProperty(kind='Room')
然后我有总是在房间（父母）或去另一个房间（父母改变）的设备，设备有文件，图片（设备的孩子）随设备移动，它到达另一个房间，例外问题（设备的孩子和房间的间接孩子）属于设备，但应显示它创建的房间号。
class Device(MainModel):
# id is ID or key of device which is child of room but becomes child of another room if changed
id = ndb.StringProperty()
name = ndb.StringProperty()
customer = ndb.KeyProperty(kind='Customer')
supporter = ndb.KeyProperty(kind='Supporter')
# device base room
base_room = ndb.KeyProperty(kind='Room')
# device actual room which can change
room = ndb.KeyProperty(kind='Room')
issue = ndb.KeyProperty(kind="issue", repeated="True")
file = ndb.KeyProperty(kind="File", repeated="True")
pics = ndb.KeyProperty(kind="Pics", repeated="True")
最后，我有来自设备的问题和门票（门票和问题的父母）
class Issue(MainModel):
# id is ID or key of issue which is child of device
id = ndb.StringProperty()
title = ndb.StringProperty()
# This is the parent of the issue model
device = ndb.KeyProperty(kind='device')
# place the issue were created
room = ndb.KeyProperty(kind='Room')
# issue child's attachments not the same as device attachments
file = ndb.KeyProperty(kind="File", repeated="True")
pics = ndb.KeyProperty(kind="Pics", repeated="True")
这是应用密钥属性的正确方法吗？看起来很混乱......特别是在这种复杂的关系设计模型中 你在想什么？我有另一种方法吗？如何动态更改父母或子女或两者的最佳或更有效的方法？
我会尝试一下，我会继续更新，请随时分享意见，为什么以及如何更好或不是。
此致