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/item/field.h> 00023 00024 namespace drizzled 00025 { 00026 00027 /* 00028 Item_insert_value -- an implementation of VALUES() function. 00029 You can use the VALUES(col_name) function in the UPDATE clause 00030 to refer to column values from the INSERT portion of the INSERT 00031 ... UPDATE statement. In other words, VALUES(col_name) in the 00032 UPDATE clause refers to the value of col_name that would be 00033 inserted, had no duplicate-key conflict occurred. 00034 In all other places this function returns NULL. 00035 */ 00036 00037 class Item_insert_value : public Item_field 00038 { 00039 public: 00040 Item *arg; 00041 Item_insert_value(Name_resolution_context *context_arg, Item *a) 00042 :Item_field(context_arg, (const char *)NULL, (const char *)NULL, 00043 (const char *)NULL), 00044 arg(a) {} 00045 bool eq(const Item *item, bool binary_cmp) const; 00046 bool fix_fields(Session *, Item **); 00047 virtual void print(String *str); 00048 int save_in_field(Field *field_arg, bool no_conversions) 00049 { 00050 return Item_field::save_in_field(field_arg, no_conversions); 00051 } 00052 /* 00053 We use RAND_TABLE_BIT to prevent Item_insert_value from 00054 being treated as a constant and precalculated before execution 00055 */ 00056 table_map used_tables() const { return RAND_TABLE_BIT; } 00057 00058 bool walk(Item_processor processor, bool walk_subquery, unsigned char *args) 00059 { 00060 return arg->walk(processor, walk_subquery, args) || 00061 (this->*processor)(args); 00062 } 00063 }; 00064 00065 } /* namespace drizzled */ 00066