Mongoose update not updating: { ok: 0, n: 0, nModified: 0 }

问题

I have a collection named "permissions" on MongoDB. I want to implement a simple update like this:

let schema = new Schema({
    title: String
  });
  let Permissions = mongoose.model("Permission", schema);
  let permission = new Permissions();

  let query = {};
  let newValues = {
    $set: {
      title: "Yes"
    }
  };
  permission.updateOne(query, newValues, (err, docs) => {
    console.log(err); // null
    console.log(docs); // { ok: 0, n: 0, nModified: 0 }
    if (err) return cast.error(err);
    return cast.ok();
  });

However I receive { ok: 0, n: 0, nModified: 0 } in console log of docs and null in console log of err.

What am I doing wrong?

回答1:

According to the docs

Models are fancy constructors compiled from Schema definitions. An instance of a model is called a document. Models are responsible for creating and reading documents from the underlying MongoDB database.

So you need to create instance during the .save() call only. Other operations(update, read, delete) applied on the existing document and hence, no need to create instance.

来源：https://stackoverflow.com/questions/52716535/mongoose-update-not-updating-ok-0-n-0-nmodified-0