我有以下型号:

class Author(db.Model):
    name = db.StringProperty()

class Story(db.Model):
    author = db.ReferenceProperty(Author)

什么是原GQL找到某个作者的所有故事。在常规的SQL,我会用连接,但我不认为在GQL这是可用的。

修改

我在寻找原始GQL方式,我知道该怎么做了Python的方式。比如像(以下可能是完全错误的):

"SELECT * FROM Story WHERE author = :1", "Shakespeare"

我想从GAE管理数据>数据查看器运行上述>查询数据存储区。我想生SQL的人可以从一个典型的MySQL或psql的shell中运行。

有帮助吗?

解决方案

EDIT2:啊,原始GQL用于在数据查看器使用...,点击 这里有一种方法:

1)运行此并获得ID号:

SELECT * FROM Author where name = 'shakespeare'

2)从先前查询中使用的ID号码,在运行此:

SELECT * FROM Story where author = key('Author', 12345)

编辑:终于,原始GQL:结果 (最简单的方法:使用隐式反向引用属性名;其形式为“modelname_set”)

qry = GqlQuery("SELECT * FROM Author WHERE name = :1", "shakespeare")
shakespeare = qry.get()
shakespeare.story_set # this property now contains all Shakespeare's stories

qry0 = GqlQuery("SELECT * FROM Author WHERE name = :1", "shakespeare")
shakespeare = qry0.get()

qry1 = GqlQuery("SELECT * FROM Story WHERE author = :1", shakespeare.key())
shakespeare_stories = qry1.fetch(10) # probably good to have some limit here

我更喜欢这种方式:

qry = Author.all()
qry.filter('name = ', 'shakespeare')
shakespeare = qry.get()

shakespeare.story_set # this property now contains all Shakespeare's stories

在更复杂的方式有时可能是必需的:

qry0 = Author.all()
qry0.filter('name = ', 'shakespeare')
shakespeare = qry0.get()

qry1 = Story.all()
qry1.filter('author = ', shakespeare.key())
shakespeare_stories = qry1.fetch(10) # probably good to have some limit here
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