Deleting a key/value from existing MongoDB entry

Question

I need to delete a certain key and value from every entry in a particular collection. I've looked into remove and that seems to be for only entire entries. Looking at update, I don't believe updating a particular key with null or an empty string would achieve what I'm trying to do. I'm very much a beginner with mongodb, so please excuse my ignorance.

Long story short, how can I turn

{
  "_id" : 1234,
  "name" : "Chris",
  "description" : "Awesome"
}

into

{
  "_id" : 1234,
  "name" : "Chris"
}

without deleting the entry and creating a new one, or using any non-mongodb commands? Thanks!

Possible duplicate of [How do I remove a field completely from Mongo?](http://stackoverflow.com/questions/6851933/how-do-i-remove-a-field-completely-from-mongo) — Frank Tan, Oct 13 '16 at 18:18

score 146 · Accepted Answer · edited Jun 21 '18 at 22:32

146

Try $unset in a call to update().

Like this:

db.collection_name.update({ _id: 1234 }, { $unset : { description : 1} })

And, as vikneshwar commented, if you want to remove one field from all (or multiple) documents you can use updateMany() like this:

db.collection_name.updateMany({}, { $unset : { description : 1} })

edited Jun 21 '18 at 22:32

Jason Sperske

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answered Apr 13 '12 at 19:04

Bee San

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17

To update all documents in a collection you can use: `db.collection_name.update({}, {$unset: { description:1}}, false, true);` The last true is for multiple documents update – Gilad Peleg Sep 16 '13 at 09:33
3

Newer versions support a more readable format: `db.example.update({},{$unset: {words:1}}, {multi: true})` – phocks Jul 04 '16 at 01:00
2

to update all documents, you can use updateMany instead of update like this ````db.collection_name.updateMany({}, { $unset : { description : 1} })```` – vikneshwar May 01 '18 at 12:30
1

What 1 does here? I mean mentioning just the key name seems to be enough. 1 is not making any specific meaning if there is no -1. Is there any possibility to have -1 as well along with "description" key? – Irfan Raza Sep 24 '18 at 09:36
Saved my time :) Thanks Bee San – Joe Sep 16 '21 at 00:29
@IrfanRaza 1 does not affect the operation, we can put anything there. – Navitas28 May 16 '22 at 13:36
I did findOneAndUpdate just to get my data as response as : `findOneAndUpdate({ _id: userid },{$unset: {'Details.Expense.2022': 1}})` and my MongoDBCompass shows as an empty object for `Expense` but when I `res.send(result)` it showed an empty array for `2022`, why did that happen ??? – Shubham Singhvi Jun 15 '22 at 07:11

score 4 · Answer 2 · edited Sep 14 '15 at 09:51

4

To reference a package and remove various "keys", try this

db['name1.name2.name3.Properties'].remove([ { "key" : "name_key1" }, { "key" : "name_key2" }, { "key" : "name_key3" } )]

edited Sep 14 '15 at 09:51

taskinoor

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answered Apr 24 '15 at 16:48

aspadacio

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score -9 · Answer 3 · answered Apr 14 '12 at 09:12

-9

Also think about upsert() that will insert your row as a new document if _id does not exist or update the existing document if any.

answered Apr 14 '12 at 09:12

Adrien M.

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Deleting a key/value from existing MongoDB entry

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