Key_part_spec Class Reference

#include <key_spec.h>

Public Member Functions
	Key_part_spec (Item *expression, enum_order order)
	Key_part_spec (const char *column_name, Item *expression, enum_order order)
	Key_part_spec (LEX_CSTRING column_name, uint prefix_length, enum_order order)
bool	operator== (const Key_part_spec &other) const
Key_part_spec *	clone (MEM_ROOT *mem_root) const
	Construct a copy of this Key_part_spec. More...
const char *	get_field_name () const
uint	get_prefix_length () const
Item *	get_expression () const
bool	is_ascending () const
bool	is_explicit () const
bool	resolve_expression (THD *thd)
	Resolve the expression that this key part contains. More...
void	set_name_and_prefix_length (const char *name, uint prefix_length)
	Set the name and the prefix length of the column this key part references. More...
bool	has_expression () const

Private Attributes
const bool	m_is_ascending
	true <=> ascending, false <=> descending. More...
const bool	m_is_explicit
	true <=> ASC/DESC is explicitly specified, false <=> implicit ASC More...
const char *	m_field_name
	The name of the column that this key part points to. More...
uint	m_prefix_length
	The prefix length of this index. More...
Item *	m_expression
	The indexed expression if this is a functional key part. More...
bool	m_has_expression
	Whether this key part has an expression or not. More...

Constructor & Destructor Documentation

Key_part_spec() [1/3]

Key_part_spec::Key_part_spec ( Item *  expression, enum_order  order  )

inline

Key_part_spec() [2/3]

Key_part_spec::Key_part_spec ( const char *  column_name, Item *  expression, enum_order  order  )

inline

Key_part_spec() [3/3]

Key_part_spec::Key_part_spec ( LEX_CSTRING  column_name, uint  prefix_length, enum_order  order  )

inline

Member Function Documentation

clone()

Key_part_spec * Key_part_spec::clone ( MEM_ROOT *  mem_root ) const

inline

Construct a copy of this Key_part_spec.

field_name is copied by-pointer as it is known to never change. At the same time 'length' may be reset in mysql_prepare_create_table, and this is why we supply it with a copy.

Returns

If out of memory, 0 is returned and an error is set in THD.

get_expression()

Item * Key_part_spec::get_expression ( ) const

inline

get_field_name()

const char * Key_part_spec::get_field_name ( ) const

inline

get_prefix_length()

uint Key_part_spec::get_prefix_length ( ) const

inline

has_expression()

bool Key_part_spec::has_expression ( ) const

inline

Return values

true	if this index has an expression. In that case, this a functional key part.
false	if this index doesn't have an expression. In that case this key part references a normal column.

is_ascending()

bool Key_part_spec::is_ascending ( ) const

inline

Return values

true	if this is an ascending index.
false	if this is a descending index.

is_explicit()

bool Key_part_spec::is_explicit ( ) const

inline

Return values

true	if the user explicitly specified the index direction when creating the index.
false	if the user didn't specify the index direction.

operator==()

bool Key_part_spec::operator==

(

const Key_part_spec &

other

)

const

resolve_expression()

bool Key_part_spec::resolve_expression

(

THD *

thd

)

Resolve the expression that this key part contains.

Should only be called if has_expression() returns true.

Parameters

thd	thread handler.

Return values

true	if an error occurred.
false	on success.

set_name_and_prefix_length()

void Key_part_spec::set_name_and_prefix_length	(	const char *	name,
		uint	prefix_length
	)

Set the name and the prefix length of the column this key part references.

The supplied column name string should have a lifetime equal to or longer than this Key_part_spec

Parameters

name	the new column that this key part points to.
prefix_length	the prefix length of the index, or 0 if no length is specified.

Member Data Documentation

m_expression

Item* Key_part_spec::m_expression

private

The indexed expression if this is a functional key part.

If this key part points to a "normal" column, m_expression is nullptr.

m_field_name

const char* Key_part_spec::m_field_name

private

The name of the column that this key part points to.

m_has_expression

bool Key_part_spec::m_has_expression

private

Whether this key part has an expression or not.

If so, this is a functional key part.

m_is_ascending

const bool Key_part_spec::m_is_ascending

private

true <=> ascending, false <=> descending.

m_is_explicit

const bool Key_part_spec::m_is_explicit

private

true <=> ASC/DESC is explicitly specified, false <=> implicit ASC

m_prefix_length

uint Key_part_spec::m_prefix_length

private

The prefix length of this index.

---

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

• sql/key_spec.h
• sql/key_spec.cc