I have objects like this
{
"_id" : ObjectId("5742be02289512cf98bf63e3"),
"name" : "test1",
"name" : "test1",
"attributes" : [
{
"name" : "x",
"color" : "0xd79c9c",
"_id" : ObjectId("5742be02289512cf98bf63e8")
},
{
"name" : "y",
"color" : "0xd79c9c",
"_id" : ObjectId("5742be02289512cf98bf63e7")
},
{
"name" : "z",
"color" : "0xd79c9c",
"_id" : ObjectId("5742be02289512cf98bf63e6")
}
],
"__v" : 6
}
And I want to update all documents, and set for each attribute new field. So I want to run single query, to update all documents at once. I think, this query will do it
db.spaces.update({}, { $set: { "attributes.0.weight": 2 } }, {multi: true})
But when I run this query, I get an error.
"code" : 16837,
"errmsg" : "The positional operator did not find the match needed from the query. Unexpanded update: attributes.$.weight"
So I cant understand why. Please help
You need to include the array field as part of the query document in order to use the positional operator
.
For example, if you want to update the first array element i.e. with { "attributes.name": "x" }
then you could follow the pattern:
db.spaces.update(
{ "attributes.name": "x" }, // <-- the array field must appear as part of the query document.
{ "$set": { "attributes.$.weight": 2 } },
{ "multi": true }
)
For the newer MongoDB versions 3.2.X
, you could use the updateMany()
method to update multiple documents within the collection based on the filter above.