Ordering Class Reference

Represents a (potentially interesting) ordering, rollup or (non-rollup) grouping. More...

#include <interesting_orders.h>

Public Types
enum class	Kind : char { kEmpty , kOrder , kRollup , kGroup }
	The kind of ordering that an Ordering instance may represent. More...
using	Elements = Bounds_checked_array< OrderElement >
	This type hold the individual elements of the ordering. More...

Public Member Functions
	Ordering ()
	Ordering (Elements elements, Kind kind)
	Ordering (const Ordering &other)
	Copy constructor. Only defined explicitly to check Valid(). More...
Ordering &	operator= (const Ordering &other)
	Assignment operator. Only defined explicitly to check Valid(). More...
Ordering	Clone (MEM_ROOT *mem_root) const
	Make a copy of *this. Allocate new memory for m_elements from mem_root. More...
Kind	GetKind () const
const Elements &	GetElements () const
Elements &	GetElements ()
size_t	size () const
void	Deduplicate ()
	Remove duplicate entries, in-place. More...

Private Member Functions
bool	Valid () const

Private Attributes
Elements	m_elements
	The ordering terms. More...
Kind	m_kind
	The kind of this ordering. More...

Friends
bool	operator== (const Ordering &a, const Ordering &b)
	Check if 'a' and 'b' has the same kind and contains the same elements. More...

Detailed Description

Represents a (potentially interesting) ordering, rollup or (non-rollup) grouping.

Member Typedef Documentation

Elements

using Ordering::Elements = Bounds_checked_array<OrderElement>

This type hold the individual elements of the ordering.

Member Enumeration Documentation

Kind

enum class Ordering::Kind : char

strong

The kind of ordering that an Ordering instance may represent.

Enumerator
kEmpty	An ordering with no elements. Such an ordering is not useful in itself, but may appear as an intermediate result.
kOrder	Specific sequence of m_elements, and specific direction of each element. Needed for e.g. ORDER BY.
kRollup	Specific sequence of m_elements, but each element may be ordered in any direction. Needed for ROLLUP:
kGroup	Elements may appear in any sequence and may be ordered in any direction. Needed for GROUP BY (with out ROLLUP), DISCTINCT, semi-join etc.

Constructor & Destructor Documentation

Ordering() [1/3]

Ordering::Ordering ( )

inline

Ordering() [2/3]

Ordering::Ordering ( Elements  elements, Kind  kind  )

inline

Ordering() [3/3]

Ordering::Ordering ( const Ordering &  other )

inline

Copy constructor. Only defined explicitly to check Valid().

Member Function Documentation

Clone()

Ordering Ordering::Clone ( MEM_ROOT *  mem_root ) const

inline

Make a copy of *this. Allocate new memory for m_elements from mem_root.

Deduplicate()

void Ordering::Deduplicate

(

)

Remove duplicate entries, in-place.

GetElements() [1/2]

Elements & Ordering::GetElements ( )

inline

GetElements() [2/2]

const Elements & Ordering::GetElements ( ) const

inline

GetKind()

Kind Ordering::GetKind ( ) const

inline

operator=()

Ordering & Ordering::operator= ( const Ordering &  other )

inline

Assignment operator. Only defined explicitly to check Valid().

size()

size_t Ordering::size ( ) const

inline

Valid()

bool Ordering::Valid ( ) const

private

Returns

true iff *this passes a consistency check.

Friends And Related Function Documentation

operator==

bool operator== ( const Ordering &  a, const Ordering &  b  )

friend

Check if 'a' and 'b' has the same kind and contains the same elements.

Member Data Documentation

m_elements

Elements Ordering::m_elements

private

The ordering terms.

m_kind

Kind Ordering::m_kind

private

The kind of this ordering.

---

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

• sql/join_optimizer/interesting_orders.h
• sql/join_optimizer/interesting_orders.cc