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MySQL 5.1: Item_func_set_user_var Class Reference

Item_func_set_user_var Class Reference

#include <item_func.h>

Inheritance diagram for Item_func_set_user_var:

[legend]Collaboration diagram for Item_func_set_user_var:

[legend]List of all members.


Public Member Functions
	Item_func_set_user_var (LEX_STRING a, Item *b)
double	val_real ()
longlong	val_int ()
String *	val_str (String *str)
my_decimal *	val_decimal (my_decimal *)
bool	update_hash (void ptr, uint length, enum Item_result type, CHARSET_INFO cs, Derivation dv, bool unsigned_arg=0)
bool	check ()
bool	update ()
enum Item_result	result_type () const
bool	fix_fields (THD thd, Item *ref)
void	fix_length_and_dec ()
void	print (String *str)
void	print_as_stmt (String *str)
const char *	func_name () const
Public Attributes
LEX_STRING	name
Private Attributes
enum Item_result	cached_result_type
user_var_entry *	entry
char	buffer [MAX_FIELD_WIDTH]
String	value
my_decimal	decimal_buff
bool	null_item
union {
longlong vint
double vreal
String * vstr
my_decimal * vdec
}	save_result

Detailed Description

Definition at line 1178 of file item_func.h.

Constructor & Destructor Documentation

Item_func_set_user_var::Item_func_set_user_var	(	LEX_STRING	a,
		Item *	b
	)			`[inline]`

Definition at line 1196 of file item_func.h.

01197     :Item_func(b), cached_result_type(INT_RESULT), name(a)
01198   {}

Member Function Documentation

bool Item_func_set_user_var::check ( )

Definition at line 3744 of file item_func.cc.

References Item_func::args, cached_result_type, DBUG_ASSERT, DBUG_ENTER, DBUG_RETURN, decimal_buff, DECIMAL_RESULT, FALSE, INT_RESULT, REAL_RESULT, ROW_RESULT, save_result, STRING_RESULT, Item::unsigned_flag, Item::val_decimal(), Item::val_int(), Item::val_real(), and Item::val_str().

Referenced by set_var_user::check(), Item_func_get_user_var::set_value(), val_decimal(), val_int(), val_real(), and val_str().

03745 {
03746   DBUG_ENTER("Item_func_set_user_var::check");
03747 
03748   switch (cached_result_type) {
03749   case REAL_RESULT:
03750   {
03751     save_result.vreal= args[0]->val_real();
03752     break;
03753   }
03754   case INT_RESULT:
03755   {
03756     save_result.vint= args[0]->val_int();
03757     unsigned_flag= args[0]->unsigned_flag;
03758     break;
03759   }
03760   case STRING_RESULT:
03761   {
03762     save_result.vstr= args[0]->val_str(&value);
03763     break;
03764   }
03765   case DECIMAL_RESULT:
03766   {
03767     save_result.vdec= args[0]->val_decimal(&decimal_buff);
03768     break;
03769   }
03770   case ROW_RESULT:
03771   default:
03772     // This case should never be chosen
03773     DBUG_ASSERT(0);
03774     break;
03775   }
03776   DBUG_RETURN(FALSE);
03777 }

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

Reimplemented from Item_func.

Definition at line 3466 of file item_func.cc.

References Item_func::args, cached_result_type, DTCollation::collation, Item::collation, DBUG_ASSERT, DERIVATION_IMPLICIT, FALSE, Item_func::fix_fields(), Item::fixed, get_variable(), name, Item::NULL_ITEM, null_item, Item::result_type(), DTCollation::set(), TRUE, and Item::type().

Referenced by set_var_user::check(), set_var_user::light_check(), and Item_func_get_user_var::set_value().

03467 {
03468   DBUG_ASSERT(fixed == 0);
03469   /* fix_fields will call Item_func_set_user_var::fix_length_and_dec */
03470   if (Item_func::fix_fields(thd, ref) ||
03471       !(entry= get_variable(&thd->user_vars, name, 1)))
03472     return TRUE;
03473   /* 
03474      Remember the last query which updated it, this way a query can later know
03475      if this variable is a constant item in the query (it is if update_query_id
03476      is different from query_id).
03477   */
03478   entry->update_query_id= thd->query_id;
03479   /*
03480     As it is wrong and confusing to associate any 
03481     character set with NULL, @a should be latin2
03482     after this query sequence:
03483 
03484       SET @a=_latin2'string';
03485       SET @a=NULL;
03486 
03487     I.e. the second query should not change the charset
03488     to the current default value, but should keep the 
03489     original value assigned during the first query.
03490     In order to do it, we don't copy charset
03491     from the argument if the argument is NULL
03492     and the variable has previously been initialized.
03493   */
03494   null_item= (args[0]->type() == NULL_ITEM);
03495   if (!entry->collation.collation || !null_item)
03496     entry->collation.set(args[0]->collation.collation, DERIVATION_IMPLICIT);
03497   collation.set(entry->collation.collation, DERIVATION_IMPLICIT);
03498   cached_result_type= args[0]->result_type();
03499   return FALSE;
03500 }

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void Item_func_set_user_var::fix_length_and_dec ( ) [virtual]

Implements Item_result_field.

Definition at line 3504 of file item_func.cc.

References Item_func::args, DTCollation::collation, Item::collation, Item::decimals, DERIVATION_IMPLICIT, Item::max_length, Item::maybe_null, and DTCollation::set().

03505 {
03506   maybe_null=args[0]->maybe_null;
03507   max_length=args[0]->max_length;
03508   decimals=args[0]->decimals;
03509   collation.set(args[0]->collation.collation, DERIVATION_IMPLICIT);
03510 }

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

Implements Item_func.

Definition at line 1212 of file item_func.h.

01212 { return "set_user_var"; }

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

Reimplemented from Item_func.

Definition at line 3884 of file item_func.cc.

References String::append(), Item_func::args, LEX_STRING::length, name, Item::print(), LEX_STRING::str, and STRING_WITH_LEN.

03885 {
03886   str->append(STRING_WITH_LEN("(@"));
03887   str->append(name.str, name.length);
03888   str->append(STRING_WITH_LEN(":="));
03889   args[0]->print(str);
03890   str->append(')');
03891 }

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void Item_func_set_user_var::print_as_stmt ( String * str )

Definition at line 3894 of file item_func.cc.

References String::append(), Item_func::args, LEX_STRING::length, name, Item::print(), LEX_STRING::str, and STRING_WITH_LEN.

03895 {
03896   str->append(STRING_WITH_LEN("set @"));
03897   str->append(name.str, name.length);
03898   str->append(STRING_WITH_LEN(":="));
03899   args[0]->print(str);
03900   str->append(')');
03901 }

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enum Item_result Item_func_set_user_var::result_type ( ) const [inline, virtual]

Reimplemented from Item.

Definition at line 1207 of file item_func.h.

References cached_result_type.

01207 { return cached_result_type; }

bool Item_func_set_user_var::update ( )

Definition at line 3797 of file item_func.cc.

References cached_result_type, DBUG_ASSERT, DBUG_ENTER, DBUG_RETURN, DECIMAL_RESULT, DERIVATION_IMPLICIT, INT_RESULT, LINT_INIT, REAL_RESULT, ROW_RESULT, save_result, STRING_RESULT, Item::unsigned_flag, and update_hash().

Referenced by Item_func_get_user_var::set_value(), set_var_user::update(), val_decimal(), val_int(), val_real(), and val_str().

03798 {
03799   bool res;
03800   DBUG_ENTER("Item_func_set_user_var::update");
03801   LINT_INIT(res);
03802 
03803   switch (cached_result_type) {
03804   case REAL_RESULT:
03805   {
03806     res= update_hash((void*) &save_result.vreal,sizeof(save_result.vreal),
03807                      REAL_RESULT, &my_charset_bin, DERIVATION_IMPLICIT);
03808     break;
03809   }
03810   case INT_RESULT:
03811   {
03812     res= update_hash((void*) &save_result.vint, sizeof(save_result.vint),
03813                      INT_RESULT, &my_charset_bin, DERIVATION_IMPLICIT,
03814                      unsigned_flag);
03815     break;
03816   }
03817   case STRING_RESULT:
03818   {
03819     if (!save_result.vstr)                                      // Null value
03820       res= update_hash((void*) 0, 0, STRING_RESULT, &my_charset_bin,
03821                        DERIVATION_IMPLICIT);
03822     else
03823       res= update_hash((void*) save_result.vstr->ptr(),
03824                        save_result.vstr->length(), STRING_RESULT,
03825                        save_result.vstr->charset(),
03826                        DERIVATION_IMPLICIT);
03827     break;
03828   }
03829   case DECIMAL_RESULT:
03830   {
03831     if (!save_result.vdec)                                      // Null value
03832       res= update_hash((void*) 0, 0, DECIMAL_RESULT, &my_charset_bin,
03833                        DERIVATION_IMPLICIT);
03834     else
03835       res= update_hash((void*) save_result.vdec,
03836                        sizeof(my_decimal), DECIMAL_RESULT,
03837                        &my_charset_bin, DERIVATION_IMPLICIT);
03838     break;
03839   }
03840   case ROW_RESULT:
03841   default:
03842     // This case should never be chosen
03843     DBUG_ASSERT(0);
03844     break;
03845   }
03846   DBUG_RETURN(res);
03847 }

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bool Item_func_set_user_var::update_hash	(	void *	ptr,
		uint	length,
		enum Item_result	type,
		CHARSET_INFO *	cs,
		Derivation	dv,
		bool	unsigned_arg = `0`
	)

Definition at line 3590 of file item_func.cc.

References Item_func::args, current_thd, and null_item.

Referenced by update().

03593 {
03594   /*
03595     If we set a variable explicitely to NULL then keep the old
03596     result type of the variable
03597   */
03598   if ((null_value= args[0]->null_value) && null_item)
03599     type= entry->type;                          // Don't change type of item
03600   if (::update_hash(entry, (null_value= args[0]->null_value),
03601                     ptr, length, type, cs, dv, unsigned_arg))
03602   {
03603     current_thd->fatal_error();     // Probably end of memory
03604     null_value= 1;
03605     return 1;
03606   }
03607   return 0;
03608 }

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

Reimplemented from Item_func.

Definition at line 3875 of file item_func.cc.

References check(), DBUG_ASSERT, Item::fixed, and update().

03876 {
03877   DBUG_ASSERT(fixed == 1);
03878   check();
03879   update();                                     // Store expression
03880   return entry->val_decimal(&null_value, val);
03881 }

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longlong Item_func_set_user_var::val_int ( ) [virtual]

Implements Item.

Definition at line 3858 of file item_func.cc.

References check(), DBUG_ASSERT, Item::fixed, and update().

03859 {
03860   DBUG_ASSERT(fixed == 1);
03861   check();
03862   update();                                     // Store expression
03863   return entry->val_int(&null_value);
03864 }

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double Item_func_set_user_var::val_real ( ) [virtual]

Implements Item.

Definition at line 3850 of file item_func.cc.

References check(), DBUG_ASSERT, Item::fixed, and update().

03851 {
03852   DBUG_ASSERT(fixed == 1);
03853   check();
03854   update();                                     // Store expression
03855   return entry->val_real(&null_value);
03856 }

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String * Item_func_set_user_var::val_str ( String * str ) [virtual]

Implements Item.

Definition at line 3866 of file item_func.cc.

References check(), DBUG_ASSERT, Item::fixed, and update().

03867 {
03868   DBUG_ASSERT(fixed == 1);
03869   check();
03870   update();                                     // Store expression
03871   return entry->val_str(&null_value, str, decimals);
03872 }