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MySQL 5.1: Item_equal Class Reference

Item_equal Class Reference

#include <item_cmpfunc.h>

Inheritance diagram for Item_equal:

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[legend]List of all members.


Public Member Functions
	Item_equal ()
	Item_equal (Item_field f1, Item_field f2)
	Item_equal (Item c, Item_field f)
	Item_equal (Item_equal *item_equal)
Item *	get_const ()
void	add (Item *c)
void	add (Item_field *f)
uint	members ()
bool	contains (Field *field)
Item_field *	get_first ()
void	merge (Item_equal *item)
void	update_const ()
enum Functype	functype () const
longlong	val_int ()
const char *	func_name () const
optimize_type	select_optimize () const
void	sort (Item_field_cmpfunc cmp, void *arg)
void	fix_length_and_dec ()
bool	fix_fields (THD thd, Item *ref)
void	update_used_tables ()
bool	walk (Item_processor processor, bool walk_subquery, byte *arg)
Item *	transform (Item_transformer transformer, byte *arg)
void	print (String *str)
CHARSET_INFO *	compare_collation ()
Private Attributes
List< Item_field >	fields
Item *	const_item
cmp_item *	eval_item
bool	cond_false
DTCollation	cmp_collation
Friends
class	Item_equal_iterator

Detailed Description

Definition at line 1267 of file item_cmpfunc.h.

Constructor & Destructor Documentation

Item_equal::Item_equal ( ) [inline]

Definition at line 1275 of file item_cmpfunc.h.

References Item_func::const_item_cache.

01276     : Item_bool_func(), const_item(0), eval_item(0), cond_false(0)
01277   { const_item_cache=0 ;}

Item_equal::Item_equal	(	Item_field *	f1,
		Item_field *	f2
	)

Definition at line 3738 of file item_cmpfunc.cc.

References Item_func::const_item_cache, f1, f2, fields, and List< T >::push_back().

03739   : Item_bool_func(), const_item(0), eval_item(0), cond_false(0)
03740 {
03741   const_item_cache= 0;
03742   fields.push_back(f1);
03743   fields.push_back(f2);
03744 }

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Item_equal::Item_equal	(	Item *	c,
		Item_field *	f
	)

Definition at line 3746 of file item_cmpfunc.cc.

References Item_func::const_item(), Item_func::const_item_cache, f, fields, and List< T >::push_back().

03747   : Item_bool_func(), eval_item(0), cond_false(0)
03748 {
03749   const_item_cache= 0;
03750   fields.push_back(f);
03751   const_item= c;
03752 }

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Item_equal::Item_equal ( Item_equal * item_equal )

Definition at line 3755 of file item_cmpfunc.cc.

References cond_false, const_item, Item_func::const_item(), Item_func::const_item_cache, fields, and List< T >::push_back().

03756   : Item_bool_func(), eval_item(0), cond_false(0)
03757 {
03758   const_item_cache= 0;
03759   List_iterator_fast<Item_field> li(item_equal->fields);
03760   Item_field *item;
03761   while ((item= li++))
03762   {
03763     fields.push_back(item);
03764   }
03765   const_item= item_equal->const_item;
03766   cond_false= item_equal->cond_false;
03767 }

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Member Function Documentation

void Item_equal::add ( Item_field * f )

Definition at line 3785 of file item_cmpfunc.cc.

References f, fields, and List< T >::push_back().

03786 {
03787   fields.push_back(f);
03788 }

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void Item_equal::add ( Item * c )

Definition at line 3769 of file item_cmpfunc.cc.

References cond_false, Item_func::const_item(), Item_func::const_item_cache, and func.

Referenced by check_equality(), merge(), and update_const().

03770 {
03771   if (cond_false)
03772     return;
03773   if (!const_item)
03774   {
03775     const_item= c;
03776     return;
03777   }
03778   Item_func_eq *func= new Item_func_eq(c, const_item);
03779   func->set_cmp_func();
03780   func->quick_fix_field();
03781   if ((cond_false= !func->val_int()))
03782     const_item_cache= 1;
03783 }

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CHARSET_INFO* Item_equal::compare_collation ( ) [inline, virtual]

Reimplemented from Item.

Definition at line 1301 of file item_cmpfunc.h.

References DTCollation::collation, Item::collation, fields, and List< T >::head().

01302   { return fields.head()->collation.collation; }

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bool Item_equal::contains ( Field * field )

Definition at line 3811 of file item_cmpfunc.cc.

References Field::eq(), Item_field::field, and fields.

Referenced by find_item_equal(), and Item_field::find_item_equal().

03812 {
03813   List_iterator_fast<Item_field> it(fields);
03814   Item_field *item;
03815   while ((item= it++))
03816   {
03817     if (field->eq(item->field))
03818         return 1;
03819   }
03820   return 0;
03821 }

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bool Item_equal::fix_fields	(	THD *	thd,
		Item **	ref
	)			`[virtual]`

Reimplemented from Item_func.

Definition at line 3946 of file item_cmpfunc.cc.

References Item_func::const_item_cache, fields, fix_length_and_dec(), Item::fixed, Item::maybe_null, Item::not_null_tables(), Item_func::not_null_tables_cache, Item::used_tables(), and Item_func::used_tables_cache.

03947 {
03948   List_iterator_fast<Item_field> li(fields);
03949   Item *item;
03950   not_null_tables_cache= used_tables_cache= 0;
03951   const_item_cache= 0;
03952   while ((item= li++))
03953   {
03954     table_map tmp_table_map;
03955     used_tables_cache|= item->used_tables();
03956     tmp_table_map= item->not_null_tables();
03957     not_null_tables_cache|= tmp_table_map;
03958     if (item->maybe_null)
03959       maybe_null=1;
03960   }
03961   fix_length_and_dec();
03962   fixed= 1;
03963   return 0;
03964 }

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void Item_equal::fix_length_and_dec ( ) [virtual]

Reimplemented from Item_bool_func.

Definition at line 4003 of file item_cmpfunc.cc.

References cmp_item::cmp_charset, cmp_collation, DTCollation::collation, Item::collation, Item_func::const_item(), eval_item, cmp_item::get_comparator(), get_first(), Item::result_type(), and STRING_RESULT.

Referenced by build_equal_items_for_cond(), and fix_fields().

04004 {
04005   Item *item= const_item ? const_item : get_first();
04006   eval_item= cmp_item::get_comparator(item->result_type(),
04007                                       item->collation.collation);
04008   if (item->result_type() == STRING_RESULT)
04009     eval_item->cmp_charset= cmp_collation.collation;
04010 }

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const char* Item_equal::func_name ( ) const [inline, virtual]

Implements Item_func.

Definition at line 1291 of file item_cmpfunc.h.

Referenced by print().

01291 { return "multiple equal"; }

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enum Functype Item_equal::functype ( ) const [inline, virtual]

Reimplemented from Item_func.

Definition at line 1289 of file item_cmpfunc.h.

References Item_func::MULT_EQUAL_FUNC.

01289 { return MULT_EQUAL_FUNC; }

Item* Item_equal::get_const ( ) [inline]

Definition at line 1281 of file item_cmpfunc.h.

References Item_func::const_item().

Referenced by add_key_fields(), eliminate_item_equal(), Item_field::equal_fields_propagator(), and get_mm_tree().

01281 { return const_item; }

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Item_field* Item_equal::get_first ( ) [inline]

Definition at line 1286 of file item_cmpfunc.h.

References fields, and List< T >::head().

Referenced by fix_length_and_dec(), and Item_field::replace_equal_field().

01286 { return fields.head(); }

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uint Item_equal::members ( )

Definition at line 3790 of file item_cmpfunc.cc.

References base_list::elements, and fields.

Referenced by build_equal_items_for_cond().

03791 {
03792   return fields.elements;
03793 }

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void Item_equal::merge ( Item_equal * item )

Definition at line 3842 of file item_cmpfunc.cc.

References add(), List< T >::concat(), cond_false, const_item, and fields.

Referenced by check_equality().

03843 {
03844   fields.concat(&item->fields);
03845   Item *c= item->const_item;
03846   if (c)
03847   {
03848     /* 
03849       The flag cond_false will be set to 1 after this, if 
03850       the multiple equality already contains a constant and its 
03851       value is  not equal to the value of c.
03852     */
03853     add(c);
03854   }
03855   cond_false|= item->cond_false;
03856 }

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

Reimplemented from Item_func.

Definition at line 4039 of file item_cmpfunc.cc.

References String::append(), Item_func::const_item(), fields, func_name(), and Item::print().

04040 {
04041   str->append(func_name());
04042   str->append('(');
04043   List_iterator_fast<Item_field> it(fields);
04044   Item *item;
04045   if (const_item)
04046     const_item->print(str);
04047   else
04048   {
04049     item= it++;
04050     item->print(str);
04051   }
04052   while ((item= it++))
04053   {
04054     str->append(',');
04055     str->append(' ');
04056     item->print(str);
04057   }
04058   str->append(')');
04059 }

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optimize_type Item_equal::select_optimize ( ) const [inline, virtual]

Reimplemented from Item_func.

Definition at line 1292 of file item_cmpfunc.h.

References Item_func::OPTIMIZE_EQUAL.

01292 { return OPTIMIZE_EQUAL; }

void Item_equal::sort	(	Item_field_cmpfunc	cmp,
		void *	arg
	)

Definition at line 3883 of file item_cmpfunc.cc.

References cmp, FALSE, fields, List_iterator< T >::ref(), List_iterator< T >::rewind(), mySTL::swap(), and TRUE.

Referenced by substitute_for_best_equal_field().

03884 {
03885   bool swap;
03886   List_iterator<Item_field> it(fields);
03887   do
03888   {
03889     Item_field *item1= it++;
03890     Item_field **ref1= it.ref();
03891     Item_field *item2;
03892 
03893     swap= FALSE;
03894     while ((item2= it++))
03895     {
03896       Item_field **ref2= it.ref();
03897       if (cmp(item1, item2, arg) < 0)
03898       {
03899         Item_field *item= *ref1;
03900         *ref1= *ref2;
03901         *ref2= item;
03902         swap= TRUE;
03903       }
03904       else
03905       {
03906         item1= item2;
03907         ref1= ref2;
03908       }
03909     }
03910     it.rewind();
03911   } while (swap);
03912 }

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Item * Item_equal::transform	(	Item_transformer	transformer,
		byte *	arg
	)			`[virtual]`

Reimplemented from Item_func.

Definition at line 4024 of file item_cmpfunc.cc.

References fields, Item::new_item(), List_iterator< T >::replace(), Item_func::transform(), and Item::transform().

Referenced by build_equal_items_for_cond().

04025 {
04026   List_iterator<Item_field> it(fields);
04027   Item *item;
04028   while ((item= it++))
04029   {
04030     Item *new_item= item->transform(transformer, arg);
04031     if (!new_item)
04032       return 0;
04033     if (new_item != item)
04034       it.replace((Item_field *) new_item);
04035   }
04036   return Item_func::transform(transformer, arg);
04037 }

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void Item_equal::update_const ( )

Definition at line 3932 of file item_cmpfunc.cc.

References add(), Item::const_item(), fields, and List_iterator< T >::remove().

03933 {
03934   List_iterator<Item_field> it(fields);
03935   Item *item;
03936   while ((item= it++))
03937   {
03938     if (item->const_item())
03939     {
03940       it.remove();
03941       add(item);
03942     }
03943   }
03944 }

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void Item_equal::update_used_tables ( ) [virtual]

Reimplemented from Item_func.

Definition at line 3966 of file item_cmpfunc.cc.

References cond_false, Item::const_item(), Item_func::const_item_cache, fields, Item_func::not_null_tables_cache, Item::update_used_tables(), Item::used_tables(), and Item_func::used_tables_cache.

Referenced by build_equal_items_for_cond().

03967 {
03968   List_iterator_fast<Item_field> li(fields);
03969   Item *item;
03970   not_null_tables_cache= used_tables_cache= 0;
03971   if ((const_item_cache= cond_false))
03972     return;
03973   while ((item=li++))
03974   {
03975     item->update_used_tables();
03976     used_tables_cache|= item->used_tables();
03977     const_item_cache&= item->const_item();
03978   }
03979 }

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longlong Item_equal::val_int ( ) [virtual]

Implements Item.

Definition at line 3981 of file item_cmpfunc.cc.

References cmp_item::cmp(), cond_false, Item_func::const_item(), st_table::const_table, eval_item, Item_field::field, fields, Item::null_value, cmp_item::store_value(), and Field::table.

03982 {
03983   Item_field *item_field;
03984   if (cond_false)
03985     return 0;
03986   List_iterator_fast<Item_field> it(fields);
03987   Item *item= const_item ? const_item : it++;
03988   if ((null_value= item->null_value))
03989     return 0;
03990   eval_item->store_value(item);
03991   while ((item_field= it++))
03992   {
03993     /* Skip fields of non-const tables. They haven't been read yet */
03994     if (item_field->field->table->const_table)
03995     {
03996       if ((null_value= item_field->null_value) || eval_item->cmp(item_field))
03997         return 0;
03998     }
03999   }
04000   return 1;
04001 }

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bool Item_equal::walk	(	Item_processor	processor,
		bool	walk_subquery,
		byte *	arg
	)			`[virtual]`

Reimplemented from Item_func.

Definition at line 4012 of file item_cmpfunc.cc.

References fields, Item_func::walk(), and Item::walk().

04013 {
04014   List_iterator_fast<Item_field> it(fields);
04015   Item *item;
04016   while ((item= it++))
04017   {
04018     if (item->walk(processor, walk_subquery, arg))
04019       return 1;
04020   }
04021   return Item_func::walk(processor, walk_subquery, arg);
04022 }