ManagedDataModelException.incompatibleDeleteRule(ManagedEntity entity, Symbol property)

Source

factory ManagedDataModelException.incompatibleDeleteRule(
    ManagedEntity entity, Symbol property) {
  return new ManagedDataModelException(
      "Relationship '${_getName(property)}' on "
      "'${_getPersistentClassName(entity)}' "
      "has both 'RelationshipDeleteRule.nullify' and 'isRequired' equal to true, which "
      "couldn't possibly be true at the same. 'isRequired' means the column "
      "can't be null and 'nullify' means the column has to be null.");
}