title: Mongoose - Model.create
body: <p>I am trying to create a new document in a collection using mongoose.
  I execute the following code:</p>
  <pre><code>const doc = await m.create(req.body); //m is the model
  </code></pre>
  <p>After sending the request using postman I receive the following error message:
  &quot;E11000 duplicate key error collection: myDB.objects index: name_1 dup key: { name: null }&quot;</p>
  <ul>
  <li>my DB contains just a doc without any null value</li>
  </ul>
  <p>Could you help me, please?</p>