MongoDB sorting orders for numeric integers and strings

mongo_shell.txt

[avocado: ~] $ mongo 
MongoDB shell version: 2.0.2
connecting to: test
> db.foo.insert({x:10});
> db.foo.insert({x:"10"});
> db.foo.insert({x:5});
> db.foo.insert({x:"5"});
> db.foo.find().sort({x:-1});
{ "_id" : ObjectId("4f383479216ae77049825406"), "x" : "5" }
{ "_id" : ObjectId("4f383470216ae77049825404"), "x" : "10" }
{ "_id" : ObjectId("4f38346b216ae77049825403"), "x" : 10 }
{ "_id" : ObjectId("4f383475216ae77049825405"), "x" : 5 }
> db.foo.find().sort({x:1});
{ "_id" : ObjectId("4f383475216ae77049825405"), "x" : 5 }
{ "_id" : ObjectId("4f38346b216ae77049825403"), "x" : 10 }
{ "_id" : ObjectId("4f383470216ae77049825404"), "x" : "10" }
{ "_id" : ObjectId("4f383479216ae77049825406"), "x" : "5" }
>

I think there are two potential routes to take:

1. try to make mongo sort by strings and integers
2. only insert strings or integers and sort that way.

If all your data is of an integer form, just force the type. Just because the base is schemaless doesn't mean that you should let your data types be anything, and the more you let the types diverge, the more difficult it will be to do things with it.