MySQL 5.1: Item_sp_variable Class Reference

Item_sp_variable Class Reference

#include <item.h>

Inheritance diagram for Item_sp_variable:

[legend]Collaboration diagram for Item_sp_variable:


Public Member Functions
	Item_sp_variable (char *sp_var_name_str, uint sp_var_name_length)
bool	fix_fields (THD thd, Item *)
double	val_real ()
longlong	val_int ()
String *	val_str (String *sp)
my_decimal *	val_decimal (my_decimal *decimal_value)
bool	is_null ()
void	make_field (Send_field *field)
bool	const_item () const
int	save_in_field (Field *field, bool no_conversions)
bool	send (Protocol protocol, String str)
Public Attributes
LEX_STRING	m_name
sp_head *	m_sp
Protected Attributes
THD *	m_thd

Detailed Description

Definition at line 889 of file item.h.

Constructor & Destructor Documentation

Item_sp_variable::Item_sp_variable	(	char *	sp_var_name_str,
		uint	sp_var_name_length
	)

Definition at line 840 of file item.cc.

References LEX_STRING::length, m_name, and LEX_STRING::str.

00842   :m_thd(0)
00843 #ifndef DBUG_OFF
00844    , m_sp(0)
00845 #endif
00846 {
00847   m_name.str= sp_var_name_str;
00848   m_name.length= sp_var_name_length;
00849 }

Member Function Documentation

bool Item_sp_variable::const_item ( ) const [inline, virtual]

Reimplemented from Item.

Definition at line 946 of file item.h.

References TRUE.

00947 {
00948   return TRUE;
00949 }

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

Reimplemented from Item.

Definition at line 852 of file item.cc.

References DTCollation::collation, Item::collation, DBUG_ASSERT, Item::decimals, DTCollation::derivation, FALSE, Item::fixed, m_thd, Item::max_length, DTCollation::set(), Item::this_item(), and Item::unsigned_flag.

00853 {
00854   Item *it;
00855 
00856   m_thd= thd; /* NOTE: this must be set before any this_xxx() */
00857   it= this_item();
00858 
00859   DBUG_ASSERT(it->fixed);
00860 
00861   max_length= it->max_length;
00862   decimals= it->decimals;
00863   unsigned_flag= it->unsigned_flag;
00864   fixed= 1;
00865   collation.set(it->collation.collation, it->collation.derivation);
00866 
00867   return FALSE;
00868 }

Here is the call graph for this function:

bool Item_sp_variable::is_null ( ) [virtual]

Reimplemented from Item.

Definition at line 937 of file item.cc.

References Item::is_null(), and Item::this_item().

00938 {
00939   return this_item()->is_null();
00940 }

Here is the call graph for this function:

void Item_sp_variable::make_field ( Send_field * field ) [inline, virtual]

Reimplemented from Item.

Definition at line 935 of file item.h.

References LEX_STRING::length, m_name, Item::make_field(), Item::name, Item::set_name(), LEX_STRING::str, strlen(), system_charset_info, and Item::this_item().

00936 {
00937   Item *it= this_item();
00938 
00939   if (name)
00940     it->set_name(name, (uint) strlen(name), system_charset_info);
00941   else
00942     it->set_name(m_name.str, m_name.length, system_charset_info);
00943   it->make_field(field);
00944 }

Here is the call graph for this function:

int Item_sp_variable::save_in_field	(	Field *	field,
		bool	no_conversions
	)			`[inline, virtual]`

Reimplemented from Item.

Definition at line 951 of file item.h.

References Item::save_in_field(), and Item::this_item().

00952 {
00953   return this_item()->save_in_field(field, no_conversions);
00954 }

Here is the call graph for this function:

bool Item_sp_variable::send	(	Protocol *	protocol,
		String *	str
	)			`[inline, virtual]`

Reimplemented from Item.

Definition at line 956 of file item.h.

References Item::send(), and Item::this_item().

00957 {
00958   return this_item()->send(protocol, str);
00959 }

Here is the call graph for this function:

my_decimal * Item_sp_variable::val_decimal ( my_decimal * decimal_value ) [virtual]

Implements Item.

Definition at line 927 of file item.cc.

References DBUG_ASSERT, Item::fixed, Item::null_value, Item::this_item(), and Item::val_decimal().

00928 {
00929   DBUG_ASSERT(fixed);
00930   Item *it= this_item();
00931   my_decimal *val= it->val_decimal(decimal_value);
00932   null_value= it->null_value;
00933   return val;
00934 }

Here is the call graph for this function:

longlong Item_sp_variable::val_int ( ) [virtual]

Implements Item.

Definition at line 881 of file item.cc.

References DBUG_ASSERT, Item::fixed, Item::null_value, Item::this_item(), and Item::val_int().

00882 {
00883   DBUG_ASSERT(fixed);
00884   Item *it= this_item();
00885   longlong ret= it->val_int();
00886   null_value= it->null_value;
00887   return ret;
00888 }

Here is the call graph for this function:

double Item_sp_variable::val_real ( ) [virtual]

Implements Item.

Definition at line 871 of file item.cc.

References DBUG_ASSERT, Item::fixed, Item::null_value, Item::this_item(), and Item::val_real().

00872 {
00873   DBUG_ASSERT(fixed);
00874   Item *it= this_item();
00875   double ret= it->val_real();
00876   null_value= it->null_value;
00877   return ret;
00878 }

Here is the call graph for this function:

String * Item_sp_variable::val_str ( String * sp ) [virtual]

Implements Item.

Definition at line 891 of file item.cc.

References String::charset(), DBUG_ASSERT, Item::fixed, String::length(), String::mark_as_const(), NULL, Item::null_value, String::ptr(), String::set(), Item::str_value, Item::this_item(), and Item::val_str().

00892 {
00893   DBUG_ASSERT(fixed);
00894   Item *it= this_item();
00895   String *res= it->val_str(sp);
00896 
00897   null_value= it->null_value;
00898 
00899   if (!res)
00900     return NULL;
00901 
00902   /*
00903     This way we mark returned value of val_str as const,
00904     so that various functions (e.g. CONCAT) won't try to
00905     modify the value of the Item. Analogous mechanism is
00906     implemented for Item_param.
00907     Without this trick Item_splocal could be changed as a
00908     side-effect of expression computation. Here is an example
00909     of what happens without it: suppose x is varchar local
00910     variable in a SP with initial value 'ab' Then
00911       select concat(x,'c');
00912     would change x's value to 'abc', as Item_func_concat::val_str()
00913     would use x's internal buffer to compute the result.
00914     This is intended behaviour of Item_func_concat. Comments to
00915     Item_param class contain some more details on the topic.
00916   */
00917 
00918   if (res != &str_value)
00919     str_value.set(res->ptr(), res->length(), res->charset());
00920   else
00921     res->mark_as_const();
00922 
00923   return &str_value;
00924 }