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 /* 00023 An object of this class: 00024 - Converts val_XXX() calls to ref->val_XXX_result() calls, like Item_ref. 00025 - Sets owner->was_null=true if it has returned a NULL value from any 00026 val_XXX() function. This allows to inject an Item_ref_null_helper 00027 object into subquery and then check if the subquery has produced a row 00028 with NULL value. 00029 */ 00030 00031 namespace drizzled 00032 { 00033 00034 class Item_ref_null_helper: public Item_ref 00035 { 00036 protected: 00037 Item_in_subselect* owner; 00038 public: 00039 Item_ref_null_helper(Name_resolution_context *context_arg, 00040 Item_in_subselect* master, Item **item, 00041 const char *table_name_arg, const char *field_name_arg) 00042 :Item_ref(context_arg, item, table_name_arg, field_name_arg), 00043 owner(master) {} 00044 double val_real(); 00045 int64_t val_int(); 00046 String* val_str(String* s); 00047 type::Decimal *val_decimal(type::Decimal *); 00048 bool val_bool(); 00049 bool get_date(type::Time <ime, uint32_t fuzzydate); 00050 virtual void print(String *str); 00051 /* 00052 we add RAND_TABLE_BIT to prevent moving this item from HAVING to WHERE 00053 */ 00054 table_map used_tables() const 00055 { 00056 return (depended_from ? 00057 OUTER_REF_TABLE_BIT : 00058 (*ref)->used_tables() | RAND_TABLE_BIT); 00059 } 00060 }; 00061 00062 } /* namespace drizzled */ 00063