Simple Question
I have MongoDb and I want to change the name of the _id property to make it MatchId
but this does not work.
It is worth mentioning that all other properties (Except the _id) could be renamed,
I have no problem with that

Can the _id property be renamed in a BsonElement?
Or it must have _id name and can not be changed?
I searched the documentation but found nothing

BsonClassMap.RegisterClassMap<MatchState>(cm =>
{
    // this does NOT rename the _id property to "MatchId"
    cm.MapIdProperty(x => x.MatchId).SetElementName("MatchId");

    // this DOES rename the "MatchCreator" property to "Creator" property
    cm.MapProperty(x => x.MatchCreator).SetElementName("Creator");
});

CodePudding user response：

Maybe copy _id into MatchId is what you need.

db.collection.update({},
[
  {
    "$set": {
      "MatchId": "$_id"
    }
  }
],
{
  "multi": true
})

mongoplayground

CodePudding user response：

Unfortunately, _id is an immutable field in MongoDB and it does not allow to change the _id of a document after you have inserted it. Once set, you cannot update the value of the _id field nor can you replace an existing document with a replacement document that has a different _id field value.