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MySQL 5.1: Item_singlerow_subselect Class Reference

Item_singlerow_subselect Class Reference

#include <item_subselect.h>

Inheritance diagram for Item_singlerow_subselect:

[legend]Collaboration diagram for Item_singlerow_subselect:

[legend]List of all members.


Public Member Functions
	Item_singlerow_subselect (st_select_lex *select_lex)
	Item_singlerow_subselect ()
void	cleanup ()
subs_type	substype ()
void	reset ()
trans_res	select_transformer (JOIN *join)
void	store (uint i, Item *item)
double	val_real ()
longlong	val_int ()
String *	val_str (String *)
my_decimal *	val_decimal (my_decimal *)
bool	val_bool ()
enum Item_result	result_type () const
void	fix_length_and_dec ()
uint	cols ()
Item *	el (uint i)
Item **	addr (uint i)
bool	check_cols (uint c)
bool	null_inside ()
void	bring_value ()
Protected Attributes
Item_cache *	value
Item_cache **	row
Friends
class	select_singlerow_subselect

Detailed Description

Definition at line 139 of file item_subselect.h.

Constructor & Destructor Documentation

Item_singlerow_subselect::Item_singlerow_subselect ( st_select_lex * select_lex )

Definition at line 301 of file item_subselect.cc.

References DBUG_ENTER, DBUG_VOID_RETURN, Item_subselect::init(), Item_subselect::max_columns, Item::maybe_null, and select_singlerow_subselect.

00302   :Item_subselect(), value(0)
00303 {
00304   DBUG_ENTER("Item_singlerow_subselect::Item_singlerow_subselect");
00305   init(select_lex, new select_singlerow_subselect(this));
00306   maybe_null= 1;
00307   max_columns= UINT_MAX;
00308   DBUG_VOID_RETURN;
00309 }

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Item_singlerow_subselect::Item_singlerow_subselect ( ) [inline]

Definition at line 145 of file item_subselect.h.

00145 :Item_subselect(), value(0), row (0) {}

Member Function Documentation

Item** Item_singlerow_subselect::addr ( uint i ) [inline, virtual]

Reimplemented from Item.

Definition at line 163 of file item_subselect.h.

References row.

00163 { return (Item**)row + i; }

void Item_singlerow_subselect::bring_value ( ) [virtual]

Reimplemented from Item.

Definition at line 485 of file item_subselect.cc.

References Item_subselect::exec().

00486 {
00487   exec();
00488 }

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bool Item_singlerow_subselect::check_cols ( uint c ) [virtual]

Reimplemented from Item.

Definition at line 465 of file item_subselect.cc.

References subselect_engine::cols(), Item_subselect::engine, ER_OPERAND_COLUMNS, my_error(), and MYF.

00466 {
00467   if (c != engine->cols())
00468   {
00469     my_error(ER_OPERAND_COLUMNS, MYF(0), c);
00470     return 1;
00471   }
00472   return 0;
00473 }

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void Item_singlerow_subselect::cleanup ( ) [virtual]

Reimplemented from Item_subselect.

Reimplemented in Item_maxmin_subselect.

Definition at line 113 of file item_subselect.cc.

References Item_subselect::cleanup(), DBUG_ENTER, DBUG_VOID_RETURN, row, and value.

Referenced by Item_maxmin_subselect::cleanup().

00114 {
00115   DBUG_ENTER("Item_singlerow_subselect::cleanup");
00116   value= 0; row= 0;
00117   Item_subselect::cleanup();
00118   DBUG_VOID_RETURN;
00119 }

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uint Item_singlerow_subselect::cols ( ) [virtual]

Reimplemented from Item.

Definition at line 460 of file item_subselect.cc.

References subselect_engine::cols(), and Item_subselect::engine.

00461 {
00462   return engine->cols();
00463 }

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Item* Item_singlerow_subselect::el ( uint i ) [inline, virtual]

Reimplemented from Item.

Definition at line 162 of file item_subselect.h.

References my_reinterpret_cast, and row.

00162 { return my_reinterpret_cast(Item*)(row[i]); }

void Item_singlerow_subselect::fix_length_and_dec ( ) [virtual]

Reimplemented from Item_subselect.

Definition at line 437 of file item_subselect.cc.

References subselect_engine::cols(), Item_subselect::engine, subselect_engine::fix_length_and_dec(), Item_subselect::max_columns, subselect_engine::may_be_null(), Item::maybe_null, subselect_engine::no_tables(), row, sql_alloc(), Item::unsigned_flag, and value.

00438 {
00439   if ((max_columns= engine->cols()) == 1)
00440   {
00441     engine->fix_length_and_dec(row= &value);
00442   }
00443   else
00444   {
00445     if (!(row= (Item_cache**) sql_alloc(sizeof(Item_cache*)*max_columns)))
00446       return;
00447     engine->fix_length_and_dec(row);
00448     value= *row;
00449   }
00450   unsigned_flag= value->unsigned_flag;
00451   /*
00452     If there are not tables in subquery then ability to have NULL value
00453     depends on SELECT list (if single row subquery have tables then it
00454     always can be NULL if there are not records fetched).
00455   */
00456   if (engine->no_tables())
00457     maybe_null= engine->may_be_null();
00458 }

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bool Item_singlerow_subselect::null_inside ( ) [virtual]

Reimplemented from Item.

Definition at line 475 of file item_subselect.cc.

References Item_subselect::max_columns, Item::null_value, and row.

00476 {
00477   for (uint i= 0; i < max_columns ; i++)
00478   {
00479     if (row[i]->null_value)
00480       return 1;
00481   }
00482   return 0;
00483 }

void Item_singlerow_subselect::reset ( ) [virtual]

Reimplemented from Item_subselect.

Definition at line 365 of file item_subselect.cc.

References Item::null_value, and value.

Referenced by val_bool(), val_decimal(), val_int(), val_real(), and val_str().

00366 {
00367   null_value= 1;
00368   if (value)
00369     value->null_value= 1;
00370 }

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enum Item_result Item_singlerow_subselect::result_type ( ) const [virtual]

Reimplemented from Item.

Definition at line 432 of file item_subselect.cc.

References Item_subselect::engine, and subselect_engine::type().

00433 {
00434   return engine->type();
00435 }

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Item_subselect::trans_res Item_singlerow_subselect::select_transformer ( JOIN * join ) [virtual]

Reimplemented from Item_subselect.

Definition at line 374 of file item_subselect.cc.

References Item_subselect::changed, JOIN::conds, DBUG_ASSERT, ER, ER_SELECT_REDUCED, Item::FIELD_ITEM, Item_subselect::have_to_be_excluded, JOIN::having, MYSQL_ERRMSG_SIZE, push_warning(), Item::REF_ITEM, Item::remove_dependence_processor(), Item_subselect::RES_OK, Item_subselect::RES_REDUCE, JOIN::select_lex, Item_subselect::substitution, Item_subselect::thd, Item::walk(), and MYSQL_ERROR::WARN_LEVEL_NOTE.

00375 {
00376   if (changed)
00377     return RES_OK;
00378 
00379   SELECT_LEX *select_lex= join->select_lex;
00380   Query_arena *arena= thd->stmt_arena;
00381  
00382   if (!select_lex->master_unit()->first_select()->next_select() &&
00383       !select_lex->table_list.elements &&
00384       select_lex->item_list.elements == 1 &&
00385       !select_lex->item_list.head()->with_sum_func &&
00386       /*
00387         We cant change name of Item_field or Item_ref, because it will
00388         prevent it's correct resolving, but we should save name of
00389         removed item => we do not make optimization if top item of
00390         list is field or reference.
00391         TODO: solve above problem
00392       */
00393       !(select_lex->item_list.head()->type() == FIELD_ITEM ||
00394         select_lex->item_list.head()->type() == REF_ITEM) &&
00395       /*
00396         switch off this optimization for prepare statement,
00397         because we do not rollback this changes
00398         TODO: make rollback for it, or special name resolving mode in 5.0.
00399       */
00400       !arena->is_stmt_prepare_or_first_sp_execute()
00401       )
00402   {
00403 
00404     have_to_be_excluded= 1;
00405     if (thd->lex->describe)
00406     {
00407       char warn_buff[MYSQL_ERRMSG_SIZE];
00408       sprintf(warn_buff, ER(ER_SELECT_REDUCED), select_lex->select_number);
00409       push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
00410                    ER_SELECT_REDUCED, warn_buff);
00411     }
00412     substitution= select_lex->item_list.head();
00413     /*
00414       as far as we moved content to upper level, field which depend of
00415       'upper' select is not really dependent => we remove this dependence
00416     */
00417     substitution->walk(&Item::remove_dependence_processor, 0,
00418                        (byte *) select_lex->outer_select());
00419     /* SELECT without FROM clause can't have WHERE or HAVING clause */
00420     DBUG_ASSERT(join->conds == 0 && join->having == 0);
00421     return RES_REDUCE;
00422   }
00423   return RES_OK;
00424 }

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void Item_singlerow_subselect::store	(	uint	i,
		Item *	item
	)

Definition at line 427 of file item_subselect.cc.

References row, and Item_cache::store().

00428 {
00429   row[i]->store(item);
00430 }

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subs_type Item_singlerow_subselect::substype ( ) [inline, virtual]

Reimplemented from Item_subselect.

Definition at line 148 of file item_subselect.h.

References Item_subselect::SINGLEROW_SUBS.

00148 { return SINGLEROW_SUBS; }

bool Item_singlerow_subselect::val_bool ( ) [virtual]

Reimplemented from Item.

Definition at line 550 of file item_subselect.cc.

References Item_subselect::exec(), Item::null_value, reset(), Item::val_bool(), and value.

00551 {
00552   if (!exec() && !value->null_value)
00553   {
00554     null_value= 0;
00555     return value->val_bool();
00556   }
00557   else
00558   {
00559     reset();
00560     return 0;
00561   }
00562 }

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my_decimal * Item_singlerow_subselect::val_decimal ( my_decimal * ) [virtual]

Implements Item.

Definition at line 535 of file item_subselect.cc.

References Item_subselect::exec(), Item::null_value, reset(), Item::val_decimal(), and value.

00536 {
00537   if (!exec() && !value->null_value)
00538   {
00539     null_value= 0;
00540     return value->val_decimal(decimal_value);
00541   }
00542   else
00543   {
00544     reset();
00545     return 0;
00546   }
00547 }

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longlong Item_singlerow_subselect::val_int ( ) [virtual]

Implements Item.

Definition at line 505 of file item_subselect.cc.

References DBUG_ASSERT, Item_subselect::exec(), Item::fixed, Item::null_value, reset(), Item::val_int(), and value.

00506 {
00507   DBUG_ASSERT(fixed == 1);
00508   if (!exec() && !value->null_value)
00509   {
00510     null_value= 0;
00511     return value->val_int();
00512   }
00513   else
00514   {
00515     reset();
00516     return 0;
00517   }
00518 }

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double Item_singlerow_subselect::val_real ( ) [virtual]

Implements Item.

Definition at line 490 of file item_subselect.cc.

References DBUG_ASSERT, Item_subselect::exec(), Item::fixed, Item::null_value, reset(), Item::val_real(), and value.

00491 {
00492   DBUG_ASSERT(fixed == 1);
00493   if (!exec() && !value->null_value)
00494   {
00495     null_value= 0;
00496     return value->val_real();
00497   }
00498   else
00499   {
00500     reset();
00501     return 0;
00502   }
00503 }

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String * Item_singlerow_subselect::val_str ( String * ) [virtual]

Implements Item.

Definition at line 520 of file item_subselect.cc.

References Item_subselect::exec(), Item::null_value, reset(), Item::val_str(), and value.

00521 {
00522   if (!exec() && !value->null_value)
00523   {
00524     null_value= 0;
00525     return value->val_str(str);
00526   }
00527   else
00528   {
00529     reset();
00530     return 0;
00531   }
00532 }