public override string ToString()
{
StringBuilder sb = new StringBuilder("alter_table_args(");
sb.Append("Dbname: ");
sb.Append(Dbname);
sb.Append(",Tbl_name: ");
sb.Append(Tbl_name);
sb.Append(",New_tbl: ");
sb.Append(New_tbl == null ? "<null>" : New_tbl.ToString());
sb.Append(")");
return sb.ToString();
}