Key_use Class Reference

#include <sql_select.h>

Collaboration diagram for Key_use:

Public Member Functions
	Key_use (TABLE *table_arg, Item *val_arg, table_map used_tables_arg, uint key_arg, uint keypart_arg, uint optimize_arg, key_part_map keypart_map_arg, ha_rows ref_table_rows_arg, bool null_rejecting_arg, bool *cond_guard_arg, uint sj_pred_no_arg)

Public Attributes
TABLE *	table
	table owning the index
Item *	val
	other side of the equality, or value if no field
table_map	used_tables
	tables used on other side of equality
uint	key
	number of index
uint	keypart
	used part of the index
uint	optimize
	0, or KEY_OPTIMIZE_*
key_part_map	keypart_map
	like keypart, but as a bitmap
ha_rows	ref_table_rows
	Estimate of how many rows for a key value.
bool	null_rejecting
bool *	cond_guard
uint	sj_pred_no

Detailed Description

Information about usage of an index to satisfy an equality condition.

Definition at line 54 of file sql_select.h.

Member Data Documentation

bool* Key_use::cond_guard

!NULL - This Key_use was created from an equality that was wrapped into an Item_func_trig_cond. This means the equality (and validity of this Key_use element) can be turned on and off. The on/off state is indicted by the pointed value: *cond_guard == TRUE <=> equality condition is on *cond_guard == FALSE <=> equality condition is off

NULL - Otherwise (the source equality can't be turned off)

Not used if the index is fulltext (such index cannot be used for equalities).

Definition at line 110 of file sql_select.h.

bool Key_use::null_rejecting

If true, the comparison this value was created from will not be satisfied if val has NULL 'value'. Not used if the index is fulltext (such index cannot be used for equalities).

Definition at line 96 of file sql_select.h.

uint Key_use::sj_pred_no

0..63 <=> This was created from semi-join IN-equality # sj_pred_no. UINT_MAX Otherwise

Not used if the index is fulltext (such index cannot be used for semijoin).

Definition at line 118 of file sql_select.h.

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

• sql/sql_select.h