Drizzled Public API Documentation

null.h

00001 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
00002  *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
00003  *
00004  *  Copyright (C) 2008 Sun Microsystems, Inc.
00005  *
00006  *  This program is free software; you can redistribute it and/or modify
00007  *  it under the terms of the GNU General Public License as published by
00008  *  the Free Software Foundation; version 2 of the License.
00009  *
00010  *  This program is distributed in the hope that it will be useful,
00011  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  *  GNU General Public License for more details.
00014  *
00015  *  You should have received a copy of the GNU General Public License
00016  *  along with this program; if not, write to the Free Software
00017  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00018  */
00019 
00020 #pragma once
00021 
00022 #include <drizzled/charset_info.h>
00023 #include <drizzled/item/basic_constant.h>
00024 
00025 namespace drizzled
00026 {
00027 
00028 class Item_null :public Item_basic_constant
00029 {
00030 public:
00031 
00032   Item_null(char *name_par=0)
00033   {
00034     maybe_null= null_value= true;
00035     max_length= 0;
00036     name= name_par ? name_par : (char*) "NULL";
00037     fixed= 1;
00038     collation.set(&my_charset_bin, DERIVATION_IGNORABLE);
00039   }
00040   enum Type type() const { return NULL_ITEM; }
00041   bool eq(const Item *item, bool binary_cmp) const;
00042   double val_real();
00043   int64_t val_int();
00044   String *val_str(String *str);
00045   type::Decimal *val_decimal(type::Decimal *);
00046   int save_in_field(Field *field, bool no_conversions);
00047   int save_safe_in_field(Field *field);
00048   bool send(plugin::Client *client, String *str);
00049   enum Item_result result_type () const { return STRING_RESULT; }
00050   enum_field_types field_type() const   { return DRIZZLE_TYPE_NULL; }
00051   bool basic_const_item() const { return 1; }
00052   Item *clone_item() { return new Item_null(name); }
00053   bool is_null() { return true; }
00054 
00055   virtual void print(String *str);
00056 
00057   Item *safe_charset_converter(const CHARSET_INFO * const tocs);
00058 };
00059 
00060 class Item_null_result :public Item_null
00061 {
00062 public:
00063   Field *result_field;
00064   Item_null_result() : Item_null(), result_field(0) {}
00065   bool is_result_field() { return result_field != 0; }
00066   void save_in_result_field(bool no_conversions)
00067   {
00068     save_in_field(result_field, no_conversions);
00069   }
00070 };
00071 
00072 } /* namespace drizzled */
00073