Drizzled Public API Documentation

get_user_var.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/function/func.h>
00023 #include <drizzled/lex_string.h>
00024 
00025 namespace drizzled
00026 {
00027 
00028 class user_var_entry;
00029 
00030 class Item_func_get_user_var :public Item_func
00031 {
00032   user_var_entry *var_entry;
00033   Item_result m_cached_result_type;
00034   Session &session;
00035 
00036 public:
00037   LEX_STRING name; // keep it public
00038   Item_func_get_user_var(Session &session_arg, LEX_STRING a):
00039     Item_func(),
00040     m_cached_result_type(STRING_RESULT),
00041     session(session_arg),
00042     name(a)
00043   {}
00044   enum Functype functype() const { return GUSERVAR_FUNC; }
00045   LEX_STRING get_name() { return name; }
00046   double val_real();
00047   int64_t val_int();
00048   type::Decimal *val_decimal(type::Decimal*);
00049   String *val_str(String* str);
00050   void fix_length_and_dec();
00051   virtual void print(String *str);
00052   enum Item_result result_type() const;
00053   /*
00054     We must always return variables as strings to guard against selects of type
00055     select @t1:=1,@t1,@t:="hello",@t from foo where (@t1:= t2.b)
00056   */
00057   const char *func_name() const { return "get_user_var"; }
00058   bool const_item() const;
00059   table_map used_tables() const
00060   { return const_item() ? 0 : RAND_TABLE_BIT; }
00061   bool eq(const Item *item, bool binary_cmp) const;
00062 };
00063 
00064 } /* namespace drizzled */
00065