ManagedDataModelException.singleEntityUniqueProperty(ManagedEntity entity, Symbol property)

Source

factory ManagedDataModelException.singleEntityUniqueProperty(
    ManagedEntity entity, Symbol property) {
  return new ManagedDataModelException("Type '${_getPersistentClassName(entity)}' "
      "has only one attribute for unique 'ManagedTableAttributes'. Must contain two or "
      "more attributes (or belongs-to relationship properties). To make this property unique, "
      "add 'ManagedColumnAttributes(unique: true)' to declaration of '${_getName(property)}'.");
}