删除mongodb中所有类型为_id的ObjectId类型的文档

Question

In my collection I have few docs with some having _id field as string and some others as type ObjectId

{_id:"xxxx"}
{_id:"yyyy"}
{_id:"ObjectId(zzz)"}
{_id:"ObjectId(xxxssssx)"}

I want to delete _id field type ObjectId(here last docs)

Is there any solution for this?

Answer 1

If your document has ObjectId you can use $type

For Example if your collection is like

{
    "_id" : "foo"
}


{
    "_id" : "bar"
}


{
    "_id" : ObjectId("546c52074e418d78ff419897")
}


{
    "_id" : ObjectId("546c52074e418d78ff419898")
}

Remove Only ObjectId

db.coll.remove({_id:{$type:7}})

if your ObjectId is like

{_id:"ObjectId(zzz)"}
{_id:"ObjectId(xxxssssx)"}

you can do it

db.coll.remove({"_id": {$regex:"^ObjectId"}})

if you want delete only one Document

db.coll.remove({"_id": {$regex:"^ObjectId"}},{justOne:true})

obviously, a specific _id

db.coll.remove({"_id" : "ObjectId(xxxssssx)"})

Answer 2

For deleting object you should write in new ObjectId so below query deleted only given object Id

db.collectioName.remove({"_id":new ObjectId("xxxssssx")})

or simply try this

db.collectioName.remove({"_id": ObjectId("xxxssssx")})

Answer 3

As you cannot update an id How update the _id of one MongoDB Document? You should delete your documents and insert them again as code below do this.

db.test.find().forEach(function(item)
{
    if(typeof item._id == 'object')
    {                  
        var id = item._id.toString().replace('ObjectId(', '').replace(')', '');               
        db.test.remove({'_id': item._id});

        item._id = id;
        db.test.insert(item);
    }
});

Answer 4

You could make use of the $type operator. The type of Object Id is 7 .

 db.collection.remove({"_id":{$type:7}})

This removes all the documents having the _id fields represented as Object Ids .