type: virtual

virtual_values: array (array of fields to be shown)

{
  "DataBaseTables": {
     "TableName": {
        "interface": {
           "fields": {
               "id_school": {"name": "Colegio","type": "virtual",  "virtual_values": ["school","city","id_school"]},
           }
        }
     }
  }
}

Shows more than one field joined by ',' in a virtual field

value: <string value>

{
  "DataBaseTables": {
     "TableName": {
        "interface": {
           "fields": {
               "v_field": {"name": "Generar","type": "virtual",  "value": "Fixed value"},
           }
        }
     }
  }
}

Shows the string in the value

"external_info": "datastore"