在哈希mongodb里面找到

Question

I have this struct in my collection:

{foo : 1, bar : 4, baz : {a : 1, b : 2 ,c : "fafofu"}}

How do I find "a" and "b" inside baz ? It does not works db.my_collection.find({baz : {a : 1, b : 2});

I don't care about if "c" is "fafofu" or "cacocu" does not matters.

Answer 1

You can use . to reach into the baz object.

db.my_collection.find({"baz.a" : 1, "baz.b" : 2});

Answer 2

Perhaps if you try the following

{foo : 1, bar : 4, a: ["1"], b: ["2"],  "c": ["fafofu"]}

You could use find / findOne :

print(db.???.findOne( { c: "fafofu" } ).foo);

http://www.mongodb.org/display/DOCS/Full+Text+Search+in+Mongo

Unfortunately I don't have the ability to test this.

print(db.???.baz.findOne( { c: "fafofu" } ).foo);

My problem is how to find the data, becauase if you don't know the key it is difficult to optimize the performance of your search. Wouldn't you agree?