Item_func_get_system_var Class Reference

Inheritance diagram for Item_func_get_system_var:

List of all members.

Public Member Functions
	Item_func_get_system_var (sys_var *var_arg, enum_var_type var_type_arg, LEX_STRING *component_arg, const char *name_arg, size_t name_len_arg)
enum Functype	functype () const
void	update_null_value ()
void	fix_length_and_dec ()
void	print (String *str, enum_query_type query_type)
bool	const_item () const
table_map	used_tables () const
enum Item_result	result_type () const
enum_field_types	field_type () const
double	val_real ()
longlong	val_int ()
String *	val_str (String *)
my_decimal *	val_decimal (my_decimal *dec_buf)
const char *	func_name () const
bool	is_written_to_binlog ()
bool	eq (const Item *item, bool binary_cmp) const
void	cleanup ()

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Member Function Documentation

bool Item_func_get_system_var::eq	(	const Item *	item,
		bool	binary_cmp
	)		const [virtual]

This function is called when:

• Comparing items in the WHERE clause (when doing where optimization)
• When trying to find an ORDER BY/GROUP BY item in the SELECT part
• When matching fields in multiple equality objects (Item_equal)

Reimplemented from Item_func.

bool Item_func_get_system_var::is_written_to_binlog

(

)

Indicates whether this system variable is written to the binlog or not.

Variables are written to the binlog as part of "status_vars" in Query_log_event, as an Intvar_log_event, or a Rand_log_event.

Returns:

true if the variable is written to the binlog, false otherwise.

void Item_func_get_system_var::print	(	String *	str,
		enum_query_type	query_type
	)		[virtual]

This method is used for to:

• to generate a view definition query (SELECT-statement);
• to generate a SQL-query for EXPLAIN EXTENDED;
• to generate a SQL-query to be shown in INFORMATION_SCHEMA;
• debug.

For more information about view definition query, INFORMATION_SCHEMA query and why they should be generated from the Item-tree,

See also:

mysql_register_view().

Reimplemented from Item_func.

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

• item_func.h
• item_func.cc