Mongo - Array query, only find where all elements match - php

Question

I'm trying to create a mongo query which will return results where all arrays have a specific element set to false.
An example data record :-
images: [
{
id: ObjectId("516bef7fc05e877b31000000"),
primary: true
},
{
id: ObjectId("516bef2ac05e879622000000"),
primary: false
},
{
id: ObjectId("516beeb7c05e879e2a000000"),
primary: false
}
],
name: "test",
etc: "etc"
I only wish to find documents where all primary fields are set to false however normally (using no query selectors or elemMatch) mongo will return this document because at least 1 of the array elements match.
How would I make mongo only return documents where they all match my search parameters?
Many thanks.

Answer 1

You can do this with the aggregation framework quite easily:
db.so.aggregate( [
{ $unwind: "$images" },
{ $group: {
_id: '$_id',
all: { $sum: 1 },
all_primary: { $sum: { $cond: [ { $eq: [ '$images.primary', true ] }, 1, 0 ] } },
images: { $push: '$images' },
name: { $first: '$name' },
etc: { $first: '$etc' },
} },
{ $project: {
_id: 1,
images: 1,
name: 1,
etc: 1,
same: { $cond: [ { $eq: [ '$all', '$all_primary' ] }, 1, 0 ] }
} },
{ $match: { 'same' : 1 } }
] );
With this as input:
{
"_id" : ObjectId("5203730bf8eaa52a846ebc3e"),
"images" : [
{
"id" : ObjectId("516bef7fc05e877b31000000"),
"primary" : true
},
{
"id" : ObjectId("516bef2ac05e879622010000"),
"primary" : true
},
{
"id" : ObjectId("516beeb7c05e879e2a000010"),
"primary" : true
}
],
"name" : "Derick",
"Etc" : true
}
{
"_id" : ObjectId("52037315f8eaa52a846ebc3f"),
"images" : [
{
"id" : ObjectId("516bef7fc05e877b31000000"),
"primary" : true
},
{
"id" : ObjectId("516bef2ac05e879622010000"),
"primary" : true
},
{
"id" : ObjectId("516beeb7c05e879e2a000020"),
"primary" : false
}
],
"name" : "James",
"Etc" : true
}
{
"_id" : ObjectId("520373621a78238235b6ffbf"),
"images" : [
{
"id" : ObjectId("516bef7fc05e877b31000000"),
"primary" : true
},
{
"id" : ObjectId("516bef2ac05e879622010000"),
"primary" : true
},
{
"id" : ObjectId("516beeb7c05e879e2a000020"),
"primary" : false
}
],
"name" : "James",
"etc" : true
}
{
"_id" : ObjectId("5203736b1a78238235b6ffc0"),
"images" : [
{
"id" : ObjectId("516bef7fc05e877b31000000"),
"primary" : true
},
{
"id" : ObjectId("516bef2ac05e879622010000"),
"primary" : true
},
{
"id" : ObjectId("516beeb7c05e879e2a000020"),
"primary" : true
}
],
"name" : "James",
"etc" : true
}
This outputs:
{
"result" : [
{
"_id" : ObjectId("5203736b1a78238235b6ffc0"),
"images" : [
{
"id" : ObjectId("516bef7fc05e877b31000000"),
"primary" : true
},
{
"id" : ObjectId("516bef2ac05e879622010000"),
"primary" : true
},
{
"id" : ObjectId("516beeb7c05e879e2a000020"),
"primary" : true
}
],
"name" : "James",
"etc" : true,
"same" : 1
},
{
"_id" : ObjectId("5203730bf8eaa52a846ebc3e"),
"images" : [
{
"id" : ObjectId("516bef7fc05e877b31000000"),
"primary" : true
},
{
"id" : ObjectId("516bef2ac05e879622010000"),
"primary" : true
},
{
"id" : ObjectId("516beeb7c05e879e2a000010"),
"primary" : true
}
],
"name" : "Derick",
"etc" : null,
"same" : 1
}
],
"ok" : 1
}

Answer 2

Wouldn't it be much simpler to exclude all documents where images has primary:true element?
{ "images" :
{ "$not" :
{"$elemMatch" : { "primary" : true }}
}
}
Naturally, this is only applicable to a boolean nested field, as in this case.

Answer 3

Having sort trouble with a similar kind of query...But just look at Dericks code, the docs say not to use $first within a $group operation, unless the $group operation is immediately after a $sort.
http://docs.mongodb.org/manual/reference/operator/aggregation/first/#grp._S_first

Answer 4

Presuming Images is a document you could use(from the shell):
db.images.find({'primary':'false'})
If Images is an object:
db.mydoc.find({'images':{'primary':'false'}})