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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2008 Sun Microsystems
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef DRIZZLED_ITEM_REF_NULL_HELPER_H
#define DRIZZLED_ITEM_REF_NULL_HELPER_H
/*
An object of this class:
- Converts val_XXX() calls to ref->val_XXX_result() calls, like Item_ref.
- Sets owner->was_null=true if it has returned a NULL value from any
val_XXX() function. This allows to inject an Item_ref_null_helper
object into subquery and then check if the subquery has produced a row
with NULL value.
*/
class Item_ref_null_helper: public Item_ref
{
protected:
Item_in_subselect* owner;
public:
Item_ref_null_helper(Name_resolution_context *context_arg,
Item_in_subselect* master, Item **item,
const char *table_name_arg, const char *field_name_arg)
:Item_ref(context_arg, item, table_name_arg, field_name_arg),
owner(master) {}
double val_real();
int64_t val_int();
String* val_str(String* s);
my_decimal *val_decimal(my_decimal *);
bool val_bool();
bool get_date(DRIZZLE_TIME *ltime, uint32_t fuzzydate);
virtual void print(String *str, enum_query_type query_type);
/*
we add RAND_TABLE_BIT to prevent moving this item from HAVING to WHERE
*/
table_map used_tables() const
{
return (depended_from ?
OUTER_REF_TABLE_BIT :
(*ref)->used_tables() | RAND_TABLE_BIT);
}
};
#endif /* DRIZZLED_ITEM_REF_NULL_HELPER_H */
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