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/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2008-2009 Sun Microsystems, Inc.
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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
*/
/**
* @file
*
* Defines the API for index hints
*/
#pragma once
namespace drizzled
{
/*
String names used to print a statement with index hints.
Keep in sync with index_hint_type.
*/
extern const char * index_hint_type_name[];
typedef unsigned char index_clause_map;
enum index_hint_type
{
INDEX_HINT_IGNORE,
INDEX_HINT_USE,
INDEX_HINT_FORCE
};
/*
Bits in index_clause_map : one for each possible FOR clause in
USE/FORCE/IGNORE INDEX index hint specification
*/
#define INDEX_HINT_MASK_JOIN (1)
#define INDEX_HINT_MASK_GROUP (1 << 1)
#define INDEX_HINT_MASK_ORDER (1 << 2)
#define INDEX_HINT_MASK_ALL (INDEX_HINT_MASK_JOIN | INDEX_HINT_MASK_GROUP | \
INDEX_HINT_MASK_ORDER)
/* Single element of an USE/FORCE/IGNORE INDEX list specified as a SQL hint */
class Index_hint : public memory::SqlAlloc
{
public:
/* The type of the hint : USE/FORCE/IGNORE */
enum index_hint_type type;
/* Where the hit applies to. A bitmask of INDEX_HINT_MASK_<place> values */
index_clause_map clause;
/*
The index name. Empty (str=NULL) name represents an empty list
USE INDEX () clause
*/
LEX_STRING key_name;
Index_hint (enum index_hint_type type_arg, index_clause_map clause_arg,
char *str, uint32_t length) :
type(type_arg), clause(clause_arg)
{
key_name.str= str;
key_name.length= length;
}
void print(Session *session, String *str);
};
} /* namespace drizzled */
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