mongodb upsert in updating an array element

Question

Want to upsert in object properties in a array of a document

Consider a document in collection m

{ "_id" : ObjectId("524bfc39e6bed5cc5a9f3a33"), 
 "x" : [       
    { "id":0.0, "name":"aaa"},{ "id":1.0, "name":"bbb"}  
 ]
}

Want to add age:100 to { "id":0.0, "name":"aaa"} . Not just age .. But but provision for upsert in the array element {}. So it can contain {age:100,"city":"amd"} (since i am getting this from the application service)

Was trying this... But did not worked as it replaced the entire array element

db.m.update({_id:ObjectId("524bfc39e6bed5cc5a9f3a33"),
     "x" : {
                "$elemMatch" : {
                        "id" : 0.0
                }
}},
{
        $set : {
                "x.$" : {
                    "age": 100
            }
        }
},
{upsert: true}
)

Changed the document to (which i did not wanted)

 { "_id" : ObjectId("524bfc39e6bed5cc5a9f3a33"), 
     "x" : [       
        { "age":100},{ "id":1.0, "name":"bbb"}  
     ]
    }

Is this possible without changing schema.

c.P.u1 · Answer 1 · 2013-10-02T13:17:32.427

7

$set : {"x.$" : {"age": 100}}

x.$ sets the entire matched array element to {age: 100}

This should work:

db.m.update({_id:ObjectId("524bfc39e6bed5cc5a9f3a33"),
"x.id": 0.0}, {$set: {"x.$.age": 100 }});

Using elemMatch:

db.test.update({x: {$elemMatch: {id: 1}}},{$set:  {"x.$.age": 44}})

Note that the upsert option here, is redundant and wouldn't work if the id isn't present in x because the positional operator $ doesn't support upserting.

edited Oct 02 '13 at 13:17

answered Oct 02 '13 at 12:11

c.P.u1

16,664
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I know this works. But i am asking if db.test.update({x: {$elemMatch: {id: 1}}},{$set: {"x.$":{"a":100,"b":200,"age": 44}}}) would work ?? Or something similar works . Note {"a":100,"b":200,"age": 44} could be object and it should "upsert" values in the matched item of the array. – shrw Oct 02 '13 at 12:35
Yes, but it'll **replace** the entire matched element with the new document: `{"a":100,"b":200,"age": 44}`. And it cannot `upsert` values because an `upsert` is performed only if a match isn't found(an element in `x` isn't present with the specified `id`). – c.P.u1 Oct 02 '13 at 12:45
>>upsert is performed only if a match isn't found,, nah! on matched documents properties are updated/ inserted – shrw Oct 02 '13 at 12:49
This is from the MongoDB docs: **If set to true, creates a new document when no document matches the query criteria. The default value is false, which does not insert a new document when no match is found.** – c.P.u1 Oct 02 '13 at 12:51
also if you try to update with upsert set, you are adding to the properties; and not replacing the document. – shrw Oct 03 '13 at 08:46
Yes, bro. What I was trying to say is that if you know, in advance, that a match will be found, then specifying the `upsert` option is redundant. `upsert` = update the matched document or insert a new one if a match isn't found. – c.P.u1 Oct 03 '13 at 09:00
2

Using of $ is not possible via upsert according to official docs: https://docs.mongodb.com/manual/reference/operator/update/positional/ – Alireza Mohamadi Dec 24 '16 at 17:29

score 0 · Answer 2 · edited May 23 '17 at 12:31

0

This is not possible without changing schema. If you can change schema to use an object to store your items (rather than an array), you can follow the approach I outlined in this answer.

edited May 23 '17 at 12:31

Community

1
1

answered Jan 25 '14 at 06:00

G-Wiz

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mongodb upsert in updating an array element

2 Answers2