Question

我一直在玩App Engine，但我似乎误解了NDB数据存储区查询。我把抛出的错误放在查询旁边。

在交互式控制台中玩游戏：

from google.appengine.ext import ndb  

class Client(ndb.Model):  
    email =  ndb.StringProperty()  
    name = ndb.StringProperty(indexed=True)  

#instantiated client instance with the parameters below. ID is 6578378068983808  
#client = Client(email = "bryan@gmail.com", name = "Bryan Wheelock" ).put()  

client = Client.query( Client.name == 'Bryan Wheelock')  
#client = Client.query( Client.ID == 6578378068983808 ) #AttributeError: type object 'Client' has no attribute 'ID'  
#client = Client.all() #AttributeError: type object 'Client' has no attribute 'all'    
#client = Client.get_by_id(6578378068983808) #THIS WORKS returns u'Bryan Wheelock'   

pprint.pprint(client.name)

我所做的示例查询完全取决于App Engine文档，我做错了什么？

Answer 1

查询

Client.query（）返回一个Query对象。

你需要从中得到结果：

query = Client.query( Client.name == 'Bryan Wheelock')
client = query.get() # first result

pprint.pprint(client.name)

或只是：

client = Client.query( Client.name == 'Bryan Wheelock').get()
pprint.pprint(client.name)

ID

id不是模型的属性，而是其键的属性。要通过其ID直接获取客户端，您可以执行

client = Client.get_by_id(id)

供您参考，您可以在此处查找模型方法：https://cloud.google.com/appengine/docs/python/ndb/modelclass

为什么我的应用引擎查询找不到我的实例？

1 个答案:

查询

ID