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MySQL 5.1: Item_maxmin_subselect Class Reference

Item_maxmin_subselect Class Reference

#include <item_subselect.h>

Inheritance diagram for Item_maxmin_subselect:

[legend]Collaboration diagram for Item_maxmin_subselect:

[legend]List of all members.


Public Member Functions
	Item_maxmin_subselect (THD thd, Item_subselect parent, st_select_lex *select_lex, bool max)
void	print (String *str)
void	cleanup ()
bool	any_value ()
void	register_value ()
void	reset_value_registration ()
Protected Attributes
bool	max
bool	was_values

Detailed Description

Definition at line 173 of file item_subselect.h.

Constructor & Destructor Documentation

Item_maxmin_subselect::Item_maxmin_subselect	(	THD *	thd,
		Item_subselect *	parent,
		st_select_lex *	select_lex,
		bool	max
	)

Definition at line 311 of file item_subselect.cc.

References Item_subselect::const_item_cache, DBUG_ENTER, DBUG_VOID_RETURN, Item_subselect::get_const_item_cache(), Item_subselect::get_used_tables_cache(), Item_subselect::init(), max, Item_subselect::max_columns, Item::maybe_null, Item_subselect::thd, and Item_subselect::used_tables_cache.

00315   :Item_singlerow_subselect(), was_values(TRUE)
00316 {
00317   DBUG_ENTER("Item_maxmin_subselect::Item_maxmin_subselect");
00318   max= max_arg;
00319   init(select_lex, new select_max_min_finder_subselect(this, max_arg));
00320   max_columns= 1;
00321   maybe_null= 1;
00322   max_columns= 1;
00323 
00324   /*
00325     Following information was collected during performing fix_fields()
00326     of Items belonged to subquery, which will be not repeated
00327   */
00328   used_tables_cache= parent->get_used_tables_cache();
00329   const_item_cache= parent->get_const_item_cache();
00330 
00331   /*
00332     this subquery always creates during preparation, so we can assign
00333     thd here
00334   */
00335   thd= thd_param;
00336 
00337   DBUG_VOID_RETURN;
00338 }

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Member Function Documentation

bool Item_maxmin_subselect::any_value ( ) [inline]

Definition at line 183 of file item_subselect.h.

References was_values.

Referenced by Item_func_not_all::empty_underlying_subquery().

00183 { return was_values; }

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void Item_maxmin_subselect::cleanup ( ) [virtual]

Reimplemented from Item_singlerow_subselect.

Definition at line 340 of file item_subselect.cc.

References Item_singlerow_subselect::cleanup(), DBUG_ENTER, DBUG_VOID_RETURN, TRUE, and was_values.

00341 {
00342   DBUG_ENTER("Item_maxmin_subselect::cleanup");
00343   Item_singlerow_subselect::cleanup();
00344 
00345   /*
00346     By default it is TRUE to avoid TRUE reporting by
00347     Item_func_not_all/Item_func_nop_all if this item was never called.
00348 
00349     Engine exec() set it to FALSE by reset_value_registration() call.
00350     select_max_min_finder_subselect::send_data() set it back to TRUE if some
00351     value will be found.
00352   */
00353   was_values= TRUE;
00354   DBUG_VOID_RETURN;
00355 }

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void Item_maxmin_subselect::print ( String * str ) [virtual]

Reimplemented from Item_subselect.

Definition at line 358 of file item_subselect.cc.

References String::append(), max, and Item_subselect::print().

00359 {
00360   str->append(max?"<max>":"<min>", 5);
00361   Item_singlerow_subselect::print(str);
00362 }

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void Item_maxmin_subselect::register_value ( ) [inline]

Definition at line 184 of file item_subselect.h.

References TRUE, and was_values.

00184 { was_values= TRUE; }

void Item_maxmin_subselect::reset_value_registration ( ) [inline, virtual]

Reimplemented from Item_subselect.

Definition at line 185 of file item_subselect.h.

References FALSE, and was_values.

00185 { was_values= FALSE; }

Member Data Documentation

bool Item_maxmin_subselect::max [protected]

Definition at line 176 of file item_subselect.h.

Referenced by Item_maxmin_subselect(), and print().

bool Item_maxmin_subselect::was_values [protected]

Definition at line 177 of file item_subselect.h.

Referenced by any_value(), cleanup(), register_value(), and reset_value_registration().

The documentation for this class was generated from the following files:

mysql/src/5.1-dbg/sql/item_subselect.h
mysql/src/5.1-dbg/sql/item_subselect.cc

Generated on Sat Sep 9 21:49:57 2006 for MySQL 5.1 by

1.4.7

The world's most popular open source database

Item_maxmin_subselect Class Reference

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation