How to update a nested array in Node.js + Mongo DB where index value is known

Question

I want to update nested array in Mongo DB (using Node.js). I am able to get the array index location.

How can I update same ? I am facing some problem while using escape character in $set

Here is what I am doing :

testCollection.update({
        "uniqueID": someID,
        "topLevelObject.innerObjectValue": innerObjectVal
    }, {
        $set: {

            'array.' + outerArrayIndex + '.value': updatedValue,

        }

    }, function(err, result) {

        if (err) {
            console.log("Error occurred while updating db info");
        }

    }
);

wdberkeley · Accepted Answer · 2014-12-18 16:13:33Z

2

It's hard to tell what the problem is because you have not included an example document or shown an error message or what goes wrong. Assuming your document looks like

{
    "_id" : 0,
    "array" : [{ "value" : 2 }, { "value" : 6 }]
}

then your above query should work, e.g.

db.test.update({ "_id" : 0 }, { "$set" : { "array.1.value" : 906 } })

will modify the document to

{
    "_id" : 0,
    "array" : [{ "value" : 2 }, { "value" : 906 }]
}

I omitted the other query condition because it isn't necessary with a unique id specified - perhaps the condition isn't matching any documents?

If you document looks like

{
    "_id" : 0,
    "array" : [2, 6]
}

then you don't need the .value in the update query:

db.test.update({ "_id" : 0 }, { "$set" : { "array.1" : 906 } })

I'd also check that the string concatenation with the variable outerArrayIndex is producing the correct field path.

answered Dec 18, 2014 at 16:13

wdberkeley

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2 Comments

DukeLover Over a year ago

yeah , you are right . I forgot to mention the document structure , but it is exactly same . Never mind , I retrieved the index after doing a find operation , then converting the result to an array and then iterating through it. I am really new to NoSQL db , pardon my ignorance. Is there any better way to design the structure ? so that I do not need to iterate

Melkor Over a year ago

I have the same problem, but mine is maybe worse. Because my data has a very deep nested structure, which makes update really hard

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