如何在Google AppEngine中过滤多个属性？ （蟒蛇）

Question

I have a problem using queries that are using more than one filter (I am using NDB instead DB):

...
foo = something.query(something.a==5, something.b<8, something.c<3).order(something.b).fetch(1)
...

I am getting this error:

Only one inequality filter per query is supported.

I could solve this problem by using something like this:

...
foo = something.query(something.a==5, something.b<8).order(something.b).fetch()
#loop through each one of those rows and add those who have foo.c<3 to some array

but that solution is not really great. Does anybody have some better idea?

Thanks

Answer 1

I had a related problem, and I used a ComputedProperty to solve it. Eg, you could have a ComputedProperty(lambda self: self.b < 8 and self.c < 3) and then just query for whether that ComputedProperty is true.

Answer 2

You need to use the query.AND or query.OR :

qry = Article.query(query.AND(Article.tags == 'python',
                              query.OR(Article.tags.IN(['ruby', 'jruby']),
                                       query.AND(Article.tags == 'php',
                                                 Article.tags != 'perl'))))

Answer 3

这是我解决的方法：

foo = something.query(ndb.query.AND(something.a==5, something.b<8, ndb.query.OR(something.c==1, something.c==2)))