title: Don't allow values ​other than the one defined to be added. MongoDB
body: <p>I have a document, called QuestionSchema, which has a field called &quot;standardAnswer&quot;, I would like to have the possibility to let this field receive only the values that I have allowed it to receive.</p>
  <p>For example, it would be &quot;positive&quot;, &quot;negative&quot;...</p>
  <p>Is there any option in the Schema creation or anything that I could do to achieve that?</p>