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How to update the _id of one MongoDB Document?

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mongodb

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Can we update _id in MongoDB?

You cannot update it but you can save a new id and remove the old id.

How do you update one property in MongoDB?

To update a single field or specific fields just use the $set operator. This will update a specific field of "citiName" by value "Jakarta Pusat" that defined by $set operator.

Can we update document in MongoDB?

MongoDB's update() and save() methods are used to update document into a collection. The update() method updates the values in the existing document while the save() method replaces the existing document with the document passed in save() method.


You cannot update it. You'll have to save the document using a new _id, and then remove the old document.

// store the document in a variable
doc = db.clients.findOne({_id: ObjectId("4cc45467c55f4d2d2a000002")})

// set a new _id on the document
doc._id = ObjectId("4c8a331bda76c559ef000004")

// insert the document, using the new _id
db.clients.insert(doc)

// remove the document with the old _id
db.clients.remove({_id: ObjectId("4cc45467c55f4d2d2a000002")})

To do it for your whole collection you can also use a loop (based on Niels example):

db.status.find().forEach(function(doc){ 
    doc._id=doc.UserId; db.status_new.insert(doc);
});
db.status_new.renameCollection("status", true);

In this case UserId was the new ID I wanted to use


In case, you want to rename _id in same collection (for instance, if you want to prefix some _ids):

db.someCollection.find().snapshot().forEach(function(doc) { 
   if (doc._id.indexOf("2019:") != 0) {
       print("Processing: " + doc._id);
       var oldDocId = doc._id;
       doc._id = "2019:" + doc._id; 
       db.someCollection.insert(doc);
       db.someCollection.remove({_id: oldDocId});
   }
});

if (doc._id.indexOf("2019:") != 0) {... needed to prevent infinite loop, since forEach picks the inserted docs, even throught .snapshot() method used.


Here I have a solution that avoid multiple requests, for loops and old document removal.

You can easily create a new idea manually using something like:_id:ObjectId() But knowing Mongo will automatically assign an _id if missing, you can use aggregate to create a $project containing all the fields of your document, but omit the field _id. You can then save it with $out

So if your document is:

{
"_id":ObjectId("5b5ed345cfbce6787588e480"),
"title": "foo",
"description": "bar"
}

Then your query will be:

    db.getCollection('myCollection').aggregate([
        {$match:
             {_id: ObjectId("5b5ed345cfbce6787588e480")}
        }        
        {$project:
            {
             title: '$title',
             description: '$description'             
            }     
        },
        {$out: 'myCollection'}
    ])