Passing More than one where condition in MONGO DB find query - mongodb

Question

I am having mongo DB collection namely student with the following document structure,
name:details:date:values
so, for an single name we will have one details list,
That details list will have multiple date lists
And each date list will have multiple values list
{
"_id" : ObjectId("51472e9fd29a736d83c27ca3"),
"name" : "Arun",
"details" : [
{
"date" : "2015-01-17",
"isNew" : false,
"isOld" : true,
"values" : [
{
"money" : "330.0",
"new" : false,
"old" : true,
},
{
"money" : "340.0",
"new" : false,
"old" : true,
}
]
},
{
"date" : "2015-01-17",
"isNew" : false,
"isOld" : false,
"values" : [
{
"money" : "330.0",
"new" : false,
"old" : false,
},
{
"money" : "340.0",
"new" : false,
"old" : false,
}
]
},
{
"date" : "2015-01-17",
"isNew" : true,
"isOld" : false,
"values" : [
{
"money" : "330.0",
"new" : true,
"old" : false,
},
{
"money" : "340.0",
"new" : true,
"old" : false,
}
]
},
{
"date" : "2013-10-19",
"isNew" : true,
"isOld" : false,
"values" : [
{
"money" : "330.0",
"new" : true,
"old" : false,
},
{
"money" : "340.0",
"new" : true,
"old" : false,
}
]
}
]
}
What is need is, i want to SELECT "all the date lists" where "name" : "Arun" and "date" : "2015-01-17",I tried this way and it is not working as expected.I am getting all the dates instead 2015-01-17 in return.
I think only one where condition is working here and that is "name" : "Arun" , Query is not considering "details.date" : "2015-01-17" in where condition.
db.student.find({ "details.date" : "2015-01-17","name" : "Arun" },{"details.date":1}).pretty()
{
"_id" : ObjectId("51472e9fd29a736d83c27ca3"),
"details" : [
{
"date" : "2015-01-17"
},
{
"date" : "2015-01-17"
},
{
"date" : "2015-01-17"
},
{
"date" : "2013-10-19"
}
]
}
I am currently using mongo 1.6.5
Can some one help me to solve this.?

Answer 1

First, you need to upgrade to a current version of MongoDB. 1.6 is now three versions behind the current "major" version.
Second, you need to fix your schema. You say "for an single name we will have one details list" - if you continue adding things into this list/array it will continue growing indefinitely and that's a bad schema design. In addition, it's more correct to group in an array values that you want to fetch together with the document - and in this case you specifically do NOT want to fetch all the values with the document, you only want to fetch an element for a particular date, plus the isOld/isNew fields suggest to me that some of these entries will correspond to out-dated values, and others will be current, and it's a bad idea to lump them together into the same document.
So my recommendation is to change your structure to be multiple documents for each student:
{
"name" : "Arun",
"date" : "2015-01-17",
"isNew" : false,
"isOld" : true,
"values" : [
{
"money" : "330.0",
"new" : false,
"old" : true,
},
{
"money" : "340.0",
"new" : false,
"old" : true,
}
]
},
{
"name" : "Arun",
"date" : "2015-01-17",
"isNew" : false,
"isOld" : true,
"values" : [
{
"money" : "330.0",
"new" : false,
"old" : false,
},
{
"money" : "340.0",
"new" : false,
"old" : false,
}
]
},
{
"name" : "Arun",
"date" : "2015-01-17",
"isNew" : false,
"isOld" : true,
"values" : [
{
"money" : "330.0",
"new" : true,
"old" : false,
},
{
"money" : "340.0",
"new" : true,
"old" : false,
}
]
},
{ "name" : "Arun",
"date" : "2013-10-19",
"isNew" : true,
"isOld" : false,
"values" : [
{
"money" : "330.0",
"new" : true,
"old" : false,
},
{
"money" : "340.0",
"new" : true,
"old" : false,
}
]
}
]
}
Now it'll be much more straight forward to query on various attributes, including being able to query in values as well as outer fields.

Answer 2

Your query is in fact matching both fields. The output is a byproduct of how MongoDB handles arrays. Matching against
"details.date" : "2015-01-17"
will return any documents in the collection where any of the entries from the details field have the right date. It will not just return the individual entries from the details array.
To do this, you may want to look at the $elemMatch operator for projection, to limit the entries in the array that are returned.

Answer 3

Here is your query,
db.sandy.aggregate(
{$unwind : "$details"},
{$match : {"details.date" : "2015-01-17","name" : "Arun"}}
)
And I guess mongo 1.6.5 does not support aggregation. refer to Doc once.