CODEWITHSUNDEEP
javascriptmongodbmeteorjavascript-objectsmeteor-autoform
blueren
blueren

Reputation: 2860

Partially updating a mongo object

I have a mongo document that looks like this : 

{
    "_id" : "cfqjJW8WZprDSJEop",
    "rName" : "z1",
    "pName" : "P-4",
    "ipAddress" : "21.1.1.12",
    "misc" : {
        "createdBy" : "admin",
        "updatedBy" : "admin",
        "creationTime" : ISODate("2016-09-15T09:43:10.953Z"),
        "updatedTime" : ISODate("2016-09-15T09:43:10.953Z")
    }
}

I have written code on my meteor helper such that during each update, only the updatedBy and updatedTime should be pushed on to the mongo document.

The misc object is something that is being added just before the insert / update.

I run into trouble when I try to update the record by using: 

doc // contains the update document being generated.
misc = {};
misc.updatedBy = //some name
misc.updatedTime = new Date();

doc.misc = misc,

r.update(id,doc); // calling meteor update

However, when the update happens, what is happening is that the query is completely replacing the misc object within the record (that contains createdBy and creationTime) with what I've passed. I end up losing the creationTime and createdBy fields.

How do I go about updating the object partially?

Since my doc object initially does not contain the misc object, I've also tried injecting in something like :

doc.$set.misc.updatedBy

But it errors out stating that updatedBy does not exist. What's the right way to update a partial object within a document?

Upvotes: 4

Views: 4201

Answers (2)

Oliver Wolf
Oliver Wolf

Reputation: 309

Per default the MongoDB update command will replace the document(s) entirely. To only update a specific field and don't touch the other fields of the matching documents use the set operator in the MongoDB update command.

Upvotes: 0

Soubhik Mondal
Soubhik Mondal

Reputation: 2666

Instead of doc.$set.misc.updatedBy

Try this:

doc = {
    "$set": {
        "misc.updatedBy": "some data"
    }
};

Here we are using the MongoDB Dot Notation to access properties of embedded documents.

Example:

var doc = {
    "$set": {
        "misc.updatedBy": "some data",
        "misc.updatedTime": new Date(),
    }
};

r.update(id, doc);

Upvotes: 6

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