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MySQL 5.1: Item_variance_field Class Reference

Item_variance_field Class Reference

#include <item_sum.h>

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List of all members.

Public Member Functions

 Item_variance_field (Item_sum_variance *item)
enum Type type () const
double val_real ()
longlong val_int ()
String * val_str (String *)
my_decimal * val_decimal (my_decimal *)
bool is_null ()
enum_field_types field_type () const
void fix_length_and_dec ()
enum Item_result result_type () const

Public Attributes

Field * field
Item_result hybrid_type
uint f_precision0
uint f_scale0
uint f_precision1
uint f_scale1
uint dec_bin_size0
uint dec_bin_size1
uint sample
uint prec_increment

Detailed Description

Definition at line 617 of file item_sum.h.

Constructor & Destructor Documentation

Item_variance_field::Item_variance_field ( Item_sum_variance *  item  ) 

Definition at line 2337 of file item_sum.cc.

References Item_sum_variance::dec_bin_size0, dec_bin_size0, Item_sum_variance::dec_bin_size1, dec_bin_size1, DECIMAL_RESULT, Item::decimals, Item_sum_variance::f_precision0, f_precision0, Item_sum_variance::f_precision1, f_precision1, Item_sum_variance::f_scale0, f_scale0, Item_sum_variance::f_scale1, f_scale1, field, Item_sum_variance::hybrid_type, hybrid_type, Item::max_length, Item::maybe_null, Item::name, Item_sum_variance::prec_increment, prec_increment, Item_result_field::result_field, Item_sum_variance::sample, sample, and Item::unsigned_flag.

02338 {
02339   name=item->name;
02340   decimals=item->decimals;
02341   max_length=item->max_length;
02342   unsigned_flag= item->unsigned_flag;
02343   field=item->result_field;
02344   maybe_null=1;
02345   sample= item->sample;
02346   prec_increment= item->prec_increment;
02347   if ((hybrid_type= item->hybrid_type) == DECIMAL_RESULT)
02348   {
02349     f_scale0= item->f_scale0;
02350     f_precision0= item->f_precision0;
02351     dec_bin_size0= item->dec_bin_size0;
02352     f_scale1= item->f_scale1;
02353     f_precision1= item->f_precision1;
02354     dec_bin_size1= item->dec_bin_size1;
02355   }
02356 }

Member Function Documentation

enum_field_types Item_variance_field::field_type (  )  const [inline, virtual]

Reimplemented from Item.

Reimplemented in Item_std_field.

Definition at line 635 of file item_sum.h.

References DECIMAL_RESULT, hybrid_type, MYSQL_TYPE_DOUBLE, and MYSQL_TYPE_NEWDECIMAL.

00636   {
00637     return hybrid_type == DECIMAL_RESULT ?
00638       MYSQL_TYPE_NEWDECIMAL : MYSQL_TYPE_DOUBLE;
00639   }

void Item_variance_field::fix_length_and_dec (  )  [inline, virtual]

Implements Item_result_field.

Definition at line 640 of file item_sum.h.

00640 {}

bool Item_variance_field::is_null (  )  [inline, virtual]

Reimplemented from Item.

Definition at line 634 of file item_sum.h.

References Item::null_value, and val_int().

00634 { (void) val_int(); return null_value; }

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

Reimplemented from Item.

Reimplemented in Item_std_field.

Definition at line 641 of file item_sum.h.

References hybrid_type.

00641 { return hybrid_type; }

enum Type Item_variance_field::type (  )  const [inline, virtual]

Implements Item.

Reimplemented in Item_std_field.

Definition at line 628 of file item_sum.h.

References Item::FIELD_VARIANCE_ITEM.

00628 {return FIELD_VARIANCE_ITEM; }

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

Implements Item.

Reimplemented in Item_std_field.

Definition at line 2388 of file item_sum.cc.

References binary2my_decimal(), count, dec_bin_size0, dec_bin_size1, E_DEC_FATAL_ERROR, f_precision0, f_precision1, f_scale0, f_scale1, field, hybrid_type, int2my_decimal(), my_decimal_div(), my_decimal_mul(), my_decimal_sub(), Item::null_value, prec_increment, Field::ptr, REAL_RESULT, sample, sint8korr, and Item::val_decimal_from_real().

Referenced by Item_std_field::val_decimal(), and Item_std_field::val_real().

02389 {
02390   // fix_fields() never calls for this Item
02391   if (hybrid_type == REAL_RESULT)
02392     return val_decimal_from_real(dec_buf);
02393 
02394   longlong count= sint8korr(field->ptr+dec_bin_size0+dec_bin_size1);
02395   if ((null_value= (count <= sample)))
02396     return 0;
02397 
02398   my_decimal dec_count, dec1_count, dec_sum, dec_sqr, tmp;
02399   int2my_decimal(E_DEC_FATAL_ERROR, count, 0, &dec_count);
02400   int2my_decimal(E_DEC_FATAL_ERROR, count-sample, 0, &dec1_count);
02401   binary2my_decimal(E_DEC_FATAL_ERROR, field->ptr,
02402                     &dec_sum, f_precision0, f_scale0);
02403   binary2my_decimal(E_DEC_FATAL_ERROR, field->ptr+dec_bin_size0,
02404                     &dec_sqr, f_precision1, f_scale1);
02405   my_decimal_mul(E_DEC_FATAL_ERROR, &tmp, &dec_sum, &dec_sum);
02406   my_decimal_div(E_DEC_FATAL_ERROR, dec_buf, &tmp, &dec_count, prec_increment);
02407   my_decimal_sub(E_DEC_FATAL_ERROR, &dec_sum, &dec_sqr, dec_buf);
02408   my_decimal_div(E_DEC_FATAL_ERROR, dec_buf,
02409                  &dec_sum, &dec1_count, prec_increment);
02410   return dec_buf;
02411 }

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longlong Item_variance_field::val_int ( void   )  [inline, virtual]

Implements Item.

Definition at line 630 of file item_sum.h.

References rint, and val_real().

Referenced by is_null().

00631   { /* can't be fix_fields()ed */ return (longlong) rint(val_real()); }

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double Item_variance_field::val_real (  )  [virtual]

Implements Item.

Reimplemented in Item_std_field.

Definition at line 2359 of file item_sum.cc.

References count, DECIMAL_RESULT, field, float8get, hybrid_type, Item::null_value, Field::ptr, sample, sint8korr, and Item::val_real_from_decimal().

Referenced by val_int(), and Item_std_field::val_real().

02360 {
02361   // fix_fields() never calls for this Item
02362   if (hybrid_type == DECIMAL_RESULT)
02363     return val_real_from_decimal();
02364 
02365   double sum,sum_sqr;
02366   longlong count;
02367   float8get(sum,field->ptr);
02368   float8get(sum_sqr,(field->ptr+sizeof(double)));
02369   count=sint8korr(field->ptr+sizeof(double)*2);
02370 
02371   if ((null_value= (count <= sample)))
02372     return 0.0;
02373 
02374   double tmp= (double) count;
02375   double tmp2= (sum_sqr - sum*sum/tmp)/(tmp - (double)sample);
02376   return tmp2 <= 0.0 ? 0.0 : tmp2;
02377 }

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

Implements Item.

Definition at line 2380 of file item_sum.cc.

References DECIMAL_RESULT, hybrid_type, Item::val_string_from_decimal(), and Item::val_string_from_real().

02381 {
02382   if (hybrid_type == DECIMAL_RESULT)
02383     return val_string_from_decimal(str);
02384   return val_string_from_real(str);
02385 }

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Member Data Documentation

uint Item_variance_field::dec_bin_size0

Definition at line 624 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

uint Item_variance_field::dec_bin_size1

Definition at line 624 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

uint Item_variance_field::f_precision0

Definition at line 622 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

uint Item_variance_field::f_precision1

Definition at line 623 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

uint Item_variance_field::f_scale0

Definition at line 622 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

uint Item_variance_field::f_scale1

Definition at line 623 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

Field* Item_variance_field::field

Definition at line 620 of file item_sum.h.

Referenced by Item_variance_field(), val_decimal(), and val_real().

Item_result Item_variance_field::hybrid_type

Definition at line 621 of file item_sum.h.

Referenced by field_type(), Item_variance_field(), result_type(), val_decimal(), Item_std_field::val_decimal(), val_real(), Item_std_field::val_real(), and val_str().

uint Item_variance_field::prec_increment

Definition at line 626 of file item_sum.h.

Referenced by Item_variance_field(), and val_decimal().

uint Item_variance_field::sample

Definition at line 625 of file item_sum.h.

Referenced by Item_variance_field(), val_decimal(), and val_real().

The documentation for this class was generated from the following files:
Generated on Sat Sep 9 21:59:14 2006 for MySQL 5.1 by  doxygen 1.4.7