How to remove a property from document - mongo / loopback

问题

I have an old property on one of my models, and I'd like to remove it from all the documents in a collection. I've tried posting via /upsertWithWhere using the id to update by:

• passing in undefined for the value which results in "http error 400 bad request"
• passing in null which just sets the property to null

I also was thinking I could do a regular POST and just overwrite each document, but these particular documents are large and I'd rather not do that.

Is there a way to simply patch it?

Edit: Need an answer that implements this Via the Loopback API.

回答1:

This query should do the trick:

db.collection('collection_name').update({},{$unset: {"old_property": ""}}, {multi:true})

Obviously, just make sure you insert into "old_property" the field name of that old property.

Explaining the query a little further...

1. "{}" matches all documents in the collection
2. "{$unset: {"old_property": ""}" removes the field(s) specified
3. "{multi:true}" (An optional field for update) Allows you to update multiple documents when set to true

Used this as a reference: https://docs.mongodb.com/manual/reference/method/db.collection.update/#multi-parameter

来源：https://stackoverflow.com/questions/42448546/how-to-remove-a-property-from-document-mongo-loopback