如何按祖先检索 Google App Engine 实体
我的 Google App Engine 数据存储区中有以下 2 个模型：
class Search(db.Model):
what = db.StringProperty()
class SearchResult(db.Model):
search = db.ReferenceProperty(Search)
title = db.StringProperty()
content = db.StringProperty()
并且，我尝试在以下函数中检索给定搜索实体的所有 SearchResult 实体：
def get_previous_search_results(what='', where=''):
search_results = None
search = db.GqlQuery("SELECT * FROM Search WHERE what = :1", what).fetch(1)
if search:
search_results = db.GqlQuery("SELECT * FROM SearchResult WHERE ANCESTOR IS :1", search[0].key()).fetch(10)
return search_results
但是，它始终返回一个空集。
有什么想法我做错了吗？我已通读 Python Datastore API 文档，这看起来像是执行此操作的正确方法，但它不起作用。
I have the following 2 models in my Google App Engine datastore:
class Search(db.Model):
what = db.StringProperty()
class SearchResult(db.Model):
search = db.ReferenceProperty(Search)
title = db.StringProperty()
content = db.StringProperty()
And, I am trying to retrieve all SearchResult entities for a given Search entity in the following function:
def get_previous_search_results(what='', where=''):
search_results = None
search = db.GqlQuery("SELECT * FROM Search WHERE what = :1", what).fetch(1)
if search:
search_results = db.GqlQuery("SELECT * FROM SearchResult WHERE ANCESTOR IS :1", search[0].key()).fetch(10)
return search_results
However, it always returns an empty set.
Any ideas what I am doing wrong? I've read through the Python Datastore API docs and this seem like the correct way to do this, but it's not working.
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您是否与父级一起创建搜索实体？ ReferenceProperty 不会创建祖先关系，并且您可能需要 search.searchresult_set，它将是对具有对搜索对象“search”的引用的 SearchResult 对象的查询。
Are you creating the Search entities with a parent? The ReferenceProperty doesn't create an ancestor relationship, and it seems likely you might want search.searchresult_set, which will be a Query for SearchResult objects that have a reference to the Search object 'search'.