"personId": {
  "dataType": "number",
  "displayName": "Person Id",
  "inputType": "none",   // will not be added to input form.
  "key": true
}

When you define an entity you can add primary or unique key which will identify the unique record. It will use to edit or delete a record.

By default system will be add 'id' a string dataType unique key, it will required to test CURD functionality using json-server, without having apis.

Once your api is ready you need to update your unique key in services and component