Field_null Class Reference

Inheritance diagram for Field_null:

List of all members.

Public Member Functions
	Field_null (uchar *ptr_arg, uint32 len_arg, enum utype unireg_check_arg, const char *field_name_arg, const CHARSET_INFO *cs)
enum_field_types	type () const
type_conversion_status	store (const char *to, uint length, const CHARSET_INFO *cs)
type_conversion_status	store (double nr)
type_conversion_status	store (longlong nr, bool unsigned_val)
type_conversion_status	store_decimal (const my_decimal *d)
type_conversion_status	reset (void)
double	val_real (void)
longlong	val_int (void)
my_decimal *	val_decimal (my_decimal *)
String *	val_str (String *value, String *value2)
int	cmp (const uchar *a, const uchar *b)
void	make_sort_key (uchar *buff, uint length)
uint32	pack_length () const
void	sql_type (String &str) const
uint32	max_display_length ()
Field_null *	clone (MEM_ROOT *mem_root) const
Field_null *	clone () const

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Member Function Documentation

Field_null* Field_null::clone

(

MEM_ROOT *

mem_root

)

const [inline, virtual]

Makes a shallow copy of the Field object.

Note:

This member function must be overridden in all concrete subclasses. Several of the Field subclasses are concrete even though they are not leaf classes, so the compiler will not always catch this.

Parameters:

mem_root

MEM_ROOT to use for memory allocation.

Return values:

NULL	If memory allocation failed.

Implements Field.

Field_null* Field_null::clone

(

)

const [inline, virtual]

Makes a shallow copy of the Field object.

Note:

This member function must be overridden in all concrete subclasses. Several of the Field subclasses are concrete even though they are not leaf classes, so the compiler will not always catch this.

Return values:

NULL	If memory allocation failed.

Implements Field.

void Field_null::make_sort_key	(	uchar *	buff,
		uint	length
	)		[inline, virtual]

Writes a copy of the current value in the record buffer, suitable for sorting using byte-by-byte comparison. Integers are always in big-endian regardless of hardware architecture. At most length bytes are written into the buffer.

Parameters:

buff	The buffer, assumed to be at least length bytes.
length	Number of bytes to write.

Implements Field.

type_conversion_status Field_null::store

(

double

nr

)

[inline, virtual]

Store double value in Field_string or Field_varstring.

Pretty prints double number into field_length characters buffer.

Parameters:

nr

number

Reimplemented from Field_str.

type_conversion_status Field_null::store_decimal

(

const my_decimal *

d

)

[inline, virtual]

Decimal representation of Field_str.

Parameters:

d	value for storing

Note:

Field_str is the base class for fields implemeting [VAR]CHAR, VAR[BINARY], BLOB/TEXT, GEOMETRY. String value should be converted to floating point value according our rules, so we use double to store value of decimal in string.

Todo:

use decimal2string?

Return values:

0	OK
!=0	error

Reimplemented from Field_str.

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The documentation for this class was generated from the following files:

• field.h
• field.cc