RelationalExpression Struct Reference

Represents an expression tree in the relational algebra of joins. More...

#include <relational_expression.h>

Public Types
enum	Type {   INNER_JOIN = static_cast<int>(JoinType::INNER) , LEFT_JOIN = static_cast<int>(JoinType::OUTER) , SEMIJOIN = static_cast<int>(JoinType::SEMI) , ANTIJOIN = static_cast<int>(JoinType::ANTI) ,   STRAIGHT_INNER_JOIN = 101 , FULL_OUTER_JOIN = static_cast<int>(JoinType::FULL_OUTER) , MULTI_INNER_JOIN = 102 , TABLE = 100 }

Public Member Functions
	RelationalExpression (THD *thd)
void	enable_semijoin_strategies (const Table_ref *tl)
const Mem_root_array< Item * > &	pushable_conditions () const
void	AddPushable (Item *cond)
	Add a condition that can be pushed down to the acces path for 'table'. More...

Public Attributes
enum RelationalExpression::Type	type
table_map	tables_in_subtree
hypergraph::NodeMap	nodes_in_subtree
const Table_ref *	table
CompanionSet *	companion_set {nullptr}
RelationalExpression *	left
RelationalExpression *	right
Mem_root_array< RelationalExpression * >	multi_children
Mem_root_array< Item * >	join_conditions
Mem_root_array< Item_eq_base * >	equijoin_conditions
Mem_root_array< CachedPropertiesForPredicate >	properties_for_join_conditions
Mem_root_array< CachedPropertiesForPredicate >	properties_for_equijoin_conditions
bool	join_conditions_reject_all_rows {false}
table_map	conditions_used_tables {0}
int	join_predicate_first {0}
int	join_predicate_last {0}
Mem_root_array< ConflictRule >	conflict_rules
uint	sj_enabled_strategies {0}

Private Attributes
Mem_root_array< Item * >	m_pushable_conditions
	Conditions that can be pushed down to the acces path for 'table'. More...

Detailed Description

Represents an expression tree in the relational algebra of joins.

Expressions are either tables, or joins of two expressions. (Joins can have join conditions, but more general filters are not represented in this structure.)

These are used as an abstract precursor to the join hypergraph; they represent the joins in the query block more or less directly, without any reordering. (The parser should largely have output a structure like this instead of Table_ref, but we are not there yet.) The only real manipulation we do on them is pushing down conditions, identifying equijoin conditions from other join conditions, and identifying join conditions that touch given tables (also a form of pushdown).

Member Enumeration Documentation

Type

enum RelationalExpression::Type

Enumerator
INNER_JOIN
LEFT_JOIN
SEMIJOIN	Left semijoin.
ANTIJOIN	Left antijoin.
STRAIGHT_INNER_JOIN
FULL_OUTER_JOIN
MULTI_INNER_JOIN
TABLE

Constructor & Destructor Documentation

RelationalExpression()

RelationalExpression::RelationalExpression ( THD *  thd )

inlineexplicit

Member Function Documentation

AddPushable()

void RelationalExpression::AddPushable ( Item *  cond )

inline

Add a condition that can be pushed down to the acces path for 'table'.

enable_semijoin_strategies()

void RelationalExpression::enable_semijoin_strategies ( const Table_ref *  tl )

inline

pushable_conditions()

const Mem_root_array< Item * > & RelationalExpression::pushable_conditions ( ) const

inline

Member Data Documentation

companion_set

CompanionSet* RelationalExpression::companion_set {nullptr}

conditions_used_tables

table_map RelationalExpression::conditions_used_tables {0}

conflict_rules

Mem_root_array<ConflictRule> RelationalExpression::conflict_rules

equijoin_conditions

Mem_root_array<Item_eq_base *> RelationalExpression::equijoin_conditions

join_conditions

Mem_root_array<Item *> RelationalExpression::join_conditions

join_conditions_reject_all_rows

bool RelationalExpression::join_conditions_reject_all_rows {false}

join_predicate_first

int RelationalExpression::join_predicate_first {0}

join_predicate_last

int RelationalExpression::join_predicate_last {0}

left

RelationalExpression* RelationalExpression::left

m_pushable_conditions

Mem_root_array<Item *> RelationalExpression::m_pushable_conditions

private

Conditions that can be pushed down to the acces path for 'table'.

multi_children

Mem_root_array<RelationalExpression *> RelationalExpression::multi_children

nodes_in_subtree

hypergraph::NodeMap RelationalExpression::nodes_in_subtree

properties_for_equijoin_conditions

Mem_root_array<CachedPropertiesForPredicate> RelationalExpression::properties_for_equijoin_conditions

properties_for_join_conditions

Mem_root_array<CachedPropertiesForPredicate> RelationalExpression::properties_for_join_conditions

right

RelationalExpression * RelationalExpression::right

sj_enabled_strategies

uint RelationalExpression::sj_enabled_strategies {0}

table

const Table_ref* RelationalExpression::table

tables_in_subtree

table_map RelationalExpression::tables_in_subtree

type

enum RelationalExpression::Type RelationalExpression::type

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The documentation for this struct was generated from the following file:

• sql/join_optimizer/relational_expression.h