MongoDB: Replace object in array

Question

I am trying to replace/update a whole object in an array to it's latest values, but I cannot get it to work.

Db looks like this: (Note: there is only 1 main object in this collection)

    {
        "_id": {...},
        "something that doesnt matter": {...},
        "var1": {
            "var2": [{...}, {...}, {...}, {...}, {...}],
            "var3": [{...}, {...}, {...}, {...}, {...}]
        },
        "something that doesnt matter": {...}
    }

I need to update a certain object from array var2, I have the object ID or there is a custom ID in the object that I can also get it with (id == updatedObject.id)

This worked but I cannot get it to work with a custom array id

await db.collection("collectionName").findOneAndUpdate(
    {"var1.var2": { $exists: true }},
    { $set: { "var1.var2.1": updatedObject } }
);

I have the ID of the object already in the array on the db, but idk how to update it from var1.var2.ID,

so basically what I need is { $set: { "var1.var2.**ID**": updatedObject } } but I cant seem to find out how to get it to work.

Cause I dont want to update the whole array, and I also dont want to update a single variable in the object. I need to update the whole object.

Thank you in advance for your replies.

Have a look at this Question, stackoverflow.com/questions/47225132/… — Mu-Majid
– Mu-Majid, Commented Jul 18, 2020 at 18:14
Have you searched around for solutions on SO? searching the with the exact title of your question gets this stackoverflow.com/questions/9200399/…, does this help? — thammada.ts
– thammada.ts, Commented Jul 19, 2020 at 6:03

Prathap Reddy · Accepted Answer · 2020-07-18 18:48:28Z

2

Have you tried as below

await db.collection("collectionName").findOneAndUpdate(
  {
    "var1.var2.id": id // id value (or any matching field) of object inside array you want to update
  },
  {
    $set: {
      "var1.var2.$": updatedObject // Update with new object
    }
  }
);

Hope this official mongodb documentation helps better for your requirement.

edited Jul 18, 2020 at 18:48

answered Jul 18, 2020 at 17:24

Prathap Reddy

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9 Comments

Bas950 Over a year ago

It always updates the first element with that, even though that isn't the correct element.

Prathap Reddy Over a year ago

Even after adding the exact id match in find query "var1.var2.id": id?

Bas950 Over a year ago

prntscr.com/tkb05f as you can see there I even did it with string to make sure it was correct but still it always does the first element in the array.

Bas950 Over a year ago

yerp it finds it, it returns the whole object ofc

Bas950 Over a year ago

:clap: :clap: That did the trick! await db.collection("collectionName").findOneAndUpdate( {"var1.var2.id": id}, { $set: { "var1.var2.$": updatedObject } } );

|

Neoflies · Accepted Answer · 2020-07-18 18:07:31Z

0

Sorry, I'm not able to comment but the above answer is almost correct except that you have to filter by var1.var2._id instead of var1.var2.id because mongodb default ID field is _id

answered Jul 18, 2020 at 18:07

Neoflies

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1 Comment

Sinaesthetic Over a year ago

I believe that's only on the document. The id in the query is on a child object within the document.

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