@Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    LoadConstraint that = (LoadConstraint) o;

    if (constraint != null ? !constraint.equals(that.constraint) : that.constraint != null)
      return false;

    return true;
  }
 @Override
 public int hashCode() {
   return constraint != null ? constraint.hashCode() : 0;
 }
 public Table getTable() {
   return constraint.getTable();
 }