Inheritance diagram for Item:

Public Types
enum	Type { FIELD_ITEM = 0, FUNC_ITEM, SUM_FUNC_ITEM, STRING_ITEM, INT_ITEM, REAL_ITEM, NULL_ITEM, VARBIN_ITEM, COPY_STR_ITEM, FIELD_AVG_ITEM, DEFAULT_VALUE_ITEM, PROC_ITEM, COND_ITEM, REF_ITEM, FIELD_STD_ITEM, FIELD_VARIANCE_ITEM, INSERT_VALUE_ITEM, SUBSELECT_ITEM, ROW_ITEM, CACHE_ITEM, TYPE_HOLDER, PARAM_ITEM, TRIGGER_FIELD_ITEM, DECIMAL_ITEM, XPATH_NODESET, XPATH_NODESET_CMP, VIEW_FIXER_ITEM }
enum	cond_result { COND_UNDEF, COND_OK, COND_TRUE, COND_FALSE }
enum	traverse_order { POSTFIX, PREFIX }
Public Member Functions
	Item (THD thd, Item item)
void	rename (char *new_name)
void	init_make_field (Send_field *tmp_field, enum enum_field_types type)
virtual void	cleanup ()
virtual void	make_field (Send_field *field)
virtual Field *	make_string_field (TABLE *table)
virtual bool	fix_fields (THD , Item *)
virtual void	fix_after_pullout (st_select_lex parent_select, st_select_lex removed_select)
void	quick_fix_field ()
type_conversion_status	save_in_field_no_warnings (Field *field, bool no_conversions)
virtual type_conversion_status	save_in_field (Field *field, bool no_conversions)
virtual void	save_org_in_field (Field *field)
virtual type_conversion_status	save_safe_in_field (Field *field)
virtual bool	send (Protocol protocol, String str)
virtual bool	eq (const Item *, bool binary_cmp) const
virtual Item_result	result_type () const
virtual enum Item_result	numeric_context_result_type () const
enum Item_result	temporal_with_date_as_number_result_type () const
virtual Item_result	cast_to_int_type () const
virtual enum_field_types	string_field_type () const
virtual enum_field_types	field_type () const
virtual enum Type	type () const =0
virtual enum_monotonicity_info	get_monotonicity_info () const
virtual longlong	val_int_endpoint (bool left_endp, bool *incl_endp)
virtual double	val_real ()=0
virtual longlong	val_int ()=0
virtual longlong	val_date_temporal ()
virtual longlong	val_time_temporal ()
longlong	val_temporal_by_field_type ()
longlong	val_temporal_with_round (enum_field_types type, uint8 dec)
ulonglong	val_uint ()
virtual String *	val_str (String *str)=0
virtual String *	val_str_ascii (String *str)
virtual my_decimal *	val_decimal (my_decimal *decimal_buffer)=0
virtual bool	val_bool ()
virtual String *	val_nodeset (String *)
type_conversion_status	save_time_in_field (Field *field)
type_conversion_status	save_date_in_field (Field *field)
type_conversion_status	save_str_value_in_field (Field field, String result)
virtual Field *	get_tmp_table_field ()
virtual Field *	tmp_table_field (TABLE *t_arg)
virtual const char *	full_name () const
virtual double	val_result ()
virtual longlong	val_int_result ()
virtual longlong	val_time_temporal_result ()
virtual longlong	val_date_temporal_result ()
virtual String *	str_result (String *tmp)
virtual my_decimal *	val_decimal_result (my_decimal *val)
virtual bool	val_bool_result ()
virtual bool	is_null_result ()
virtual table_map	used_tables () const
virtual table_map	resolved_used_tables () const
virtual table_map	not_null_tables () const
virtual bool	basic_const_item () const
virtual Item *	clone_item ()
virtual cond_result	eq_cmp_result () const
uint	float_length (uint decimals_par) const
virtual uint	decimal_precision () const
int	decimal_int_part () const
virtual uint	time_precision ()
virtual uint	datetime_precision ()
virtual bool	const_item () const
virtual bool	const_during_execution () const
virtual void	print (String *str, enum_query_type query_type)
void	print_item_w_name (String *, enum_query_type query_type)
void	print_for_order (String *str, enum_query_type query_type, bool used_alias)
virtual void	update_used_tables ()
virtual void	split_sum_func (THD *thd, Ref_ptr_array ref_pointer_array, List< Item > &fields)
void	split_sum_func2 (THD thd, Ref_ptr_array ref_pointer_array, List< Item > &fields, Item *ref, bool skip_registered)
virtual bool	get_date (MYSQL_TIME *ltime, uint fuzzydate)=0
virtual bool	get_time (MYSQL_TIME *ltime)=0
virtual bool	get_timeval (struct timeval tm, int warnings)
virtual bool	get_date_result (MYSQL_TIME *ltime, uint fuzzydate)
virtual bool	is_null ()
virtual void	update_null_value ()
virtual void	top_level_item ()
virtual void	set_result_field (Field *field)
virtual bool	is_result_field ()
virtual bool	is_bool_func ()
virtual void	save_in_result_field (bool no_conversions)
virtual void	no_rows_in_result ()
virtual Item *	copy_or_same (THD *thd)
virtual Item *	copy_andor_structure (THD *thd, bool real_items=false)
virtual Item *	real_item ()
virtual Item *	substitutional_item ()
virtual void	set_runtime_created ()
virtual Item *	get_tmp_table_item (THD *thd)
virtual const CHARSET_INFO *	compare_collation ()
virtual const CHARSET_INFO *	charset_for_protocol (void) const
virtual bool	walk (Item_processor processor, bool walk_subquery, uchar *arg)
virtual Item *	transform (Item_transformer transformer, uchar *arg)
virtual Item *	compile (Item_analyzer analyzer, uchar *arg_p, Item_transformer transformer, uchar arg_t)
virtual void	traverse_cond (Cond_traverser traverser, void *arg, traverse_order order)
virtual bool	intro_version (uchar *int_arg)
virtual bool	remove_dependence_processor (uchar *arg)
virtual bool	remove_fixed (uchar *arg)
virtual bool	cleanup_processor (uchar *arg)
virtual bool	collect_item_field_processor (uchar *arg)
virtual bool	add_field_to_set_processor (uchar *arg)
virtual bool	remove_column_from_bitmap (uchar *arg)
virtual bool	find_item_in_field_list_processor (uchar *arg)
virtual bool	change_context_processor (uchar *context)
virtual bool	reset_query_id_processor (uchar *query_id_arg)
virtual bool	find_item_processor (uchar *arg)
virtual bool	register_field_in_read_map (uchar *arg)
virtual bool	inform_item_in_cond_of_tab (uchar *join_tab_index)
virtual bool	clean_up_after_removal (uchar *arg)
virtual bool	cache_const_expr_analyzer (uchar **arg)
virtual Item *	cache_const_expr_transformer (uchar *arg)
virtual bool	item_field_by_name_analyzer (uchar **arg)
virtual Item *	item_field_by_name_transformer (uchar *arg)
virtual bool	equality_substitution_analyzer (uchar **arg)
virtual Item *	equality_substitution_transformer (uchar *arg)
virtual bool	check_partition_func_processor (uchar *bool_arg)
virtual bool	subst_argument_checker (uchar **arg)
virtual bool	explain_subquery_checker (uchar **arg)
virtual Item *	explain_subquery_propagator (uchar *arg)
virtual Item *	equal_fields_propagator (uchar *arg)
virtual bool	set_no_const_sub (uchar *arg)
virtual Item *	replace_equal_field (uchar *arg)
virtual bool	check_valid_arguments_processor (uchar *bool_arg)
virtual bool	find_function_processor (uchar *arg)
virtual Item *	this_item ()
virtual const Item *	this_item () const
virtual Item **	this_item_addr (THD thd, Item *addr_arg)
virtual uint	cols ()
virtual Item *	element_index (uint i)
virtual Item **	addr (uint i)
virtual bool	check_cols (uint c)
virtual bool	null_inside ()
virtual void	bring_value ()
Field *	tmp_table_field_from_field_type (TABLE *table, bool fixed_length)
virtual Item_field *	field_for_view_update ()
virtual Item *	neg_transformer (THD *thd)
virtual Item *	update_value_transformer (uchar *select_arg)
virtual Item *	safe_charset_converter (const CHARSET_INFO *tocs)
void	delete_self ()
virtual bool	is_splocal ()
virtual Settable_routine_parameter *	get_settable_routine_parameter ()
bool	is_temporal_with_date () const
bool	is_temporal_with_date_and_time () const
bool	is_temporal_with_time () const
bool	is_temporal () const
bool	has_compatible_context (Item *item) const
virtual Field::geometry_type	get_geometry_type () const
String *	check_well_formed_result (String *str, bool send_error=0)
bool	eq_by_collation (Item item, bool binary_cmp, const CHARSET_INFO cs)
virtual bool	is_expensive ()
virtual bool	can_be_evaluated_now () const
uint32	max_char_length () const
void	fix_length_and_charset (uint32 max_char_length_arg, const CHARSET_INFO *cs)
void	fix_char_length (uint32 max_char_length_arg)
void	fix_char_length_ulonglong (ulonglong max_char_length_arg)
void	fix_length_and_charset_datetime (uint32 max_char_length_arg)
void	fix_length_and_dec_and_charset_datetime (uint32 max_char_length_arg, uint8 dec_arg)
virtual bool	is_outer_field () const
bool	is_blob_field () const
virtual bool	has_subquery () const
virtual bool	has_stored_program () const
virtual bool	created_by_in2exists () const
	Whether this Item was created by the IN->EXISTS subquery transformation.
Static Public Member Functions
static void *	operator new (size_t size) throw ()
static void *	operator new (size_t size, MEM_ROOT *mem_root) throw ()
static void	operator delete (void *ptr, size_t size)
static void	operator delete (void ptr, MEM_ROOT mem_root)
static const CHARSET_INFO *	default_charset ()
Public Attributes
uint	rsize
String	str_value
Item_name_string	item_name
Item_name_string	orig_name
Item *	next
uint32	max_length
int	marker
uint8	decimals
my_bool	maybe_null
my_bool	null_value
my_bool	unsigned_flag
my_bool	with_sum_func
my_bool	fixed
DTCollation	collation
Item_result	cmp_context
bool	runtime_item
Protected Member Functions
String *	val_string_from_real (String *str)
String *	val_string_from_int (String *str)
String *	val_string_from_decimal (String *str)
String *	val_string_from_date (String *str)
String *	val_string_from_datetime (String *str)
String *	val_string_from_time (String *str)
my_decimal *	val_decimal_from_real (my_decimal *decimal_value)
my_decimal *	val_decimal_from_int (my_decimal *decimal_value)
my_decimal *	val_decimal_from_string (my_decimal *decimal_value)
my_decimal *	val_decimal_from_date (my_decimal *decimal_value)
my_decimal *	val_decimal_from_time (my_decimal *decimal_value)
longlong	val_int_from_decimal ()
longlong	val_int_from_date ()
longlong	val_int_from_time ()
longlong	val_int_from_datetime ()
double	val_real_from_decimal ()
bool	get_date_from_string (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_real (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_decimal (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_int (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_time (MYSQL_TIME *ltime)
bool	get_date_from_numeric (MYSQL_TIME *ltime, uint fuzzydate)
bool	get_date_from_non_temporal (MYSQL_TIME *ltime, uint fuzzydate)
bool	get_time_from_string (MYSQL_TIME *ltime)
bool	get_time_from_real (MYSQL_TIME *ltime)
bool	get_time_from_decimal (MYSQL_TIME *ltime)
bool	get_time_from_int (MYSQL_TIME *ltime)
bool	get_time_from_date (MYSQL_TIME *ltime)
bool	get_time_from_datetime (MYSQL_TIME *ltime)
bool	get_time_from_numeric (MYSQL_TIME *ltime)
bool	get_time_from_non_temporal (MYSQL_TIME *ltime)
Protected Attributes
my_bool	with_subselect
my_bool	with_stored_program
bool	tables_locked_cache

Constructor & Destructor Documentation

Item::Item	(	THD *	thd,
		Item *	item
	)

Constructor used by Item_field, Item_ref & aggregate (sum) functions.

Used for duplicating lists in processing queries with temporary tables.

Member Function Documentation

bool Item::cache_const_expr_analyzer ( uchar ** arg ) [virtual]

Check if an item is a constant one and can be cached.

Parameters:

arg	[out] != NULL <=> Cache this item.

Returns:: TRUE Go deeper in item tree.; FALSE Don't go deeper in item tree.

Item * Item::cache_const_expr_transformer ( uchar * arg ) [virtual]

Cache item if needed.

Parameters:

arg	!= NULL <=> Cache this item.

Returns:: cache if cache needed.; this otherwise.

bool Item::can_be_evaluated_now ( ) const [virtual]

Check if it is OK to evaluate the item now.

Returns:: true if the item can be evaluated in the current statement state.

Return values:

true	The item can be evaluated now.
false	The item can not be evaluated now, (i.e. depend on non locked table).

Note:: Help function to avoid optimize or exec call during prepare phase.

String * Item::check_well_formed_result	(	String *	str,
		bool	send_error = `0`
	)

Verifies that the input string is well-formed according to its character set.

Parameters:

send_error If true, call my_error if string is not well-formed.

Will truncate input string if it is not well-formed.

Returns:: If well-formed: input string. If not well-formed: if strict mode: NULL pointer and we set this Item's value to NULL if not strict mode: input string truncated up to last good character

virtual bool Item::clean_up_after_removal ( uchar * arg ) [inline, virtual]

Clean up after removing the item from the item tree.

Parameters:

arg	Pointer to the st_select_lex from which the walk started, i.e., the st_select_lex that contained the clause that was removed.

Reimplemented in Item_sum, and Item_subselect.

bool Item::cleanup_processor ( uchar * arg ) [virtual]

cleanup() item if it is 'fixed'.

Parameters:

arg	a dummy parameter, is not used here

virtual Item* Item::copy_andor_structure	(	THD *	thd,
		bool	real_items = `false`
	)		`[inline, virtual]`

Parameters:

real_items True <=> in the copy, replace any Item_ref with its real_item()

Todo:: this argument should be always false and removed in WL#7082.

Reimplemented in Item_cond_or, and Item_cond_and.

uint Item::datetime_precision ( ) [virtual]

DATETIME precision of the item: 0..6

Reimplemented in Item_temporal_func.

bool Item::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 in Item_cache, Item_trigger_field, Item_insert_value, Item_default_value, Item_direct_view_ref, Item_ref, Item_hex_string, Item_string, Item_float, Item_decimal, Item_int, Item_param, Item_null, Item_field, Item_func_match, Item_func_get_system_var, Item_func_get_user_var, Item_extract, Item_date_add_interval, Item_func_date_format, Item_datetime_literal, Item_time_literal, Item_func_set_collation, Item_date_literal, Item_char_typecast, Item_func_opt_neg, and Item_func.

virtual bool Item::find_function_processor ( uchar * arg ) [inline, virtual]

Find a function of a given type

Parameters:

arg	the function type to search (enum Item_func::Functype)

Returns:

Return values:

TRUE	the function type we're searching for is found
FALSE	the function type wasn't found

This function can be used (together with Item::walk()) to find functions in an item tree fragment.

Reimplemented in Item_func.

virtual void Item::fix_after_pullout	(	st_select_lex *	parent_select,
		st_select_lex *	removed_select
	)		`[inline, virtual]`

Fix after tables have been moved from one select_lex level to the parent level, e.g by semijoin conversion. Basically re-calculate all attributes dependent on the tables.

Parameters:

parent_select	select_lex that tables are moved to.
removed_select	select_lex that tables are moved away from, child of parent_select.

Reimplemented in Item_outer_ref, Item_ref, Item_ident, Item_cond, Item_func_in, Item_func_if, Item_func_between, Item_in_subselect, Item_in_optimizer, Item_subselect, Item_func, and Item_row.

bool Item::get_date_from_decimal	(	MYSQL_TIME *	ltime,
		uint	flags
	)		`[protected]`

Convert val_decimal() to date in MYSQL_TIME

bool Item::get_date_from_int	(	MYSQL_TIME *	ltime,
		uint	flags
	)		`[protected]`

Convert val_int() to date in MYSQL_TIME

bool Item::get_date_from_non_temporal	(	MYSQL_TIME *	ltime,
		uint	fuzzydate
	)		`[protected]`

Convert a non-temporal type to date

Get the value of the function as a MYSQL_TIME structure. As a extra convenience the time structure is reset on error!

bool Item::get_date_from_numeric	(	MYSQL_TIME *	ltime,
		uint	fuzzydate
	)		`[protected]`

Convert a numeric type to date

bool Item::get_date_from_real	(	MYSQL_TIME *	ltime,
		uint	flags
	)		`[protected]`

Convert val_real() to date in MYSQL_TIME

bool Item::get_date_from_string	(	MYSQL_TIME *	ltime,
		uint	flags
	)		`[protected]`

Convert val_str() to date in MYSQL_TIME

bool Item::get_date_from_time ( MYSQL_TIME * ltime ) [protected]

Convert get_time() from time to date in MYSQL_TIME

bool Item::get_time_from_date ( MYSQL_TIME * ltime ) [protected]

Convert date to time

bool Item::get_time_from_datetime ( MYSQL_TIME * ltime ) [protected]

Convert datetime to time

bool Item::get_time_from_decimal ( MYSQL_TIME * ltime ) [protected]

Convert val_decimal() to time in MYSQL_TIME

bool Item::get_time_from_int ( MYSQL_TIME * ltime ) [protected]

Convert val_int() to time in MYSQL_TIME

bool Item::get_time_from_non_temporal ( MYSQL_TIME * ltime ) [protected]

Convert a non-temporal type to time

Get time value from int, real, decimal or string.

As a extra convenience the time structure is reset on error!

bool Item::get_time_from_numeric ( MYSQL_TIME * ltime ) [protected]

Convert a numeric type to time

bool Item::get_time_from_real ( MYSQL_TIME * ltime ) [protected]

Convert val_real() to time in MYSQL_TIME

bool Item::get_time_from_string ( MYSQL_TIME * ltime ) [protected]

Convert val_str() to time in MYSQL_TIME

bool Item::get_timeval	(	struct timeval *	tm,
		int *	warnings
	)		`[virtual]`

Get timestamp in "struct timeval" format.

Return values:

false	on success
true	on error

If argument is NULL, sets null_value. Otherwise: if invalid DATETIME value, or a valid DATETIME value but which is out of the supported Unix timestamp range, sets 'tm' to 0.

Reimplemented in Item_field.

bool Item::has_compatible_context ( Item * item ) const [inline]

Check whether this and the given item has compatible comparison context. Used by the equality propagation. See Item_field::equal_fields_propagator.

Returns:: TRUE if the context is the same or if fields could be compared as DATETIME values by the Arg_comparator. FALSE otherwise.

virtual bool Item::has_subquery ( ) const [inline, virtual]

Checks if this item or any of its decendents contains a subquery.

Reimplemented in Item_ref.

bool Item::is_blob_field ( ) const

Check if an item either is a blob field, or will be represented as a BLOB field if a field is created based on this item.

Return values:

TRUE	If a field based on this item will be a BLOB field,
FALSE	Otherwise.

virtual bool Item::item_field_by_name_analyzer ( uchar ** arg ) [inline, virtual]

Analyzer for finding Item_field by name

Parameters:

arg	Field name to search for

Returns:: TRUE Go deeper in item tree. (Found Item or not an Item_field); FALSE Don't go deeper in item tree. (Item_field with other name)

Reimplemented in Item_field.

virtual Item* Item::item_field_by_name_transformer ( uchar * arg ) [inline, virtual]

Simple transformer that returns the argument if this is an Item_field. The new item will inherit it's name to maintain aliases.

Parameters:

arg	Item to replace Item_field

Returns:: argument if this is an Item_field; this otherwise.

Reimplemented in Item_field.

Field * Item::make_string_field ( TABLE * table ) [virtual]

Create a field to hold a string value from an item.

If max_length > CONVERT_IF_BIGGER_TO_BLOB create a blob
If max_length > 0 create a varchar
If max_length == 0 create a CHAR(0) (or VARCHAR(0) if we are grouping)

Parameters:

table Table for which the field is created

Reimplemented in Item_func_group_concat.

virtual enum Item_result Item::numeric_context_result_type ( ) const [inline, virtual]

Result type when an item appear in a numeric context. See Field::numeric_context_result_type() for more comments.

Reimplemented in Item_field.

virtual void Item::print	(	String *	str,
		enum_query_type	query_type
	)		`[inline, 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 in Item_cache, Item_trigger_field, Item_insert_value, Item_default_value, Item_temporal_with_ref, Item_ref_null_helper, Item_ref, Item_hex_string, Item_static_string_func, Item_string, Item_static_float_func, Item_float, Item_decimal, Item_uint, Item_int, Item_param, Item_null, Item_field, Item_ident, Item_name_const, Item_case_expr, Item_aggregate_ref, Item_func_match, Item_splocal, Item_func_get_system_var, Item_equal, Item_user_var_as_out_param, Item_func_get_user_var, Item_func_set_user_var, Item_cond, Item_func_regex, Item_func_isnotnull, Item_func_get_format, Item_func_group_concat, Item_func_timestamp_diff, Item_func_add_time, Item_func_in, Item_datetime_typecast, Item_time_typecast, Item_date_typecast, Item_func_case, Item_extract, Item_date_add_interval, Item_func_benchmark, Item_func_bit_neg, Item_func_bit, Item_func_locate, Item_datetime_literal, Item_time_literal, Item_func_set_collation, Item_func_conv_charset, Item_func_nullif, Item_date_literal, Item_func_binary, Item_char_typecast, Item_func_strcmp, Item_func_between, Item_func_int_div, Item_func_format, Item_func_make_set, Item_decimal_typecast, Item_func_unsigned, Item_func_not_all, Item_func_signed, Item_func_trig_cond, Item_allany_subselect, Item_num_op, Item_in_subselect, Item_func_not, Item_sum, Item_bool_func2, Item_exists_subselect, Item_func_trim, Item_maxmin_subselect, Item_func_truth, Item_func, Item_subselect, and Item_row.

void Item::print_for_order	(	String *	str,
		enum_query_type	query_type,
		bool	used_alias
	)

Prints the item when it's part of ORDER BY and GROUP BY.

Parameters:

str	String to print to
query_type	How to format the item
used_alias	Whether item was referenced with alias.

"SELECT (subq) GROUP BY (same_subq)" confuses ONLY_FULL_GROUP_BY (it does not see that both subqueries are the same, raises an error). To avoid hitting this problem, if the original query was: "SELECT expression AS x GROUP BY x", we print "GROUP BY x", not "GROUP BY expression". Same for ORDER BY. This has practical importance for views created as "CREATE VIEW v SELECT (subq) AS x GROUP BY x" (print_order() is used to write the view's definition in the frm file). We make one exception: if the view is merge-able, its ORDER clause will be merged into the parent query's. If an identifier in the merged ORDER clause is allowed to be either an alias or an expression of the view's underlying tables, resolution is difficult: it may be to be found in the underlying tables of the view, or in the SELECT list of the view; unlike other ORDER elements directly originating from the parent query. To avoid this problem, if the view is merge-able, we print the expression. This does not cause problems with only_full_group_by, because a merge-able view never has GROUP BY.

See also:: mysql_register_view().

virtual bool Item::remove_column_from_bitmap ( uchar * arg ) [inline, virtual]

Visitor interface for removing all column expressions (Item_field) in this expression tree from a bitmap. walk()

Parameters:

arg	A MY_BITMAP* cast to unsigned char*, where the bits represent Field::field_index values.

Reimplemented in Item_field.

void Item::rename ( char * new_name )

rename item (used for views, cleanup() return original name).

Parameters:

new_name new name of item;

virtual table_map Item::resolved_used_tables ( ) const [inline, virtual]

Return used table information for the level this item is resolved on.

For fields, this returns the table the item is resolved from.
For all other items, this behaves like used_tables().

Note:: : Use this function with caution. External calls to this function should only be made for class objects derived from Item_ident. Item::resolved_used_tables is for internal use only, in order to process fields underlying a view column reference.

Reimplemented in Item_cache, Item_ref, and Item_field.

type_conversion_status Item::save_in_field	(	Field *	field,
		bool	no_conversions
	)		`[virtual]`

Save a temporal value in packed longlong format into a Field. Used in optimizer.

Parameters:

OUT	field The field to set the value to.

Return values:

0	On success.
>0	In error.

Reimplemented in Item_cache_str, Item_insert_value, Item_default_value, Item_copy_decimal, Item_copy_float, Item_copy_int, Item_copy_string, Item_copy, Item_int_with_ref, Item_ref, Item_hex_string, Item_string, Item_float, Item_decimal, Item_uint, Item_temporal, Item_int, Item_param, Item_null, Item_field, Item_name_const, Item_sp_variable, Item_func_set_user_var, Item_func_now, Item_time_func, Item_datetime_func, Item_date_func, Item_temporal_hybrid_func, and Item_func_user.

bool Item::send	(	Protocol *	protocol,
		String *	buffer
	)		`[virtual]`

This is only called from items that is not of type item_field.

Reimplemented in Item_ref, Item_null, Item_field, Item_name_const, Item_sp_variable, and Item_func_set_user_var.

void Item::split_sum_func2	(	THD *	thd,
		Ref_ptr_array	ref_pointer_array,
		List< Item > &	fields,
		Item **	ref,
		bool	skip_registered
	)

Move SUM items out from item tree and replace with reference.

Parameters:

thd	Thread handler
ref_pointer_array	Pointer to array of reference fields
fields	All fields in select
ref	Pointer to item
skip_registered	<=> function be must skipped for registered SUM items

Note:: This is from split_sum_func2() for items that should be split

All found SUM items are added FIRST in the fields list and we replace the item with a reference.

thd->fatal_error() may be called if we are out of memory

enum Item_result Item::temporal_with_date_as_number_result_type ( ) const [inline]

Similar to result_type() but makes DATE, DATETIME, TIMESTAMP pretend to be numbers rather than strings.

uint Item::time_precision ( ) [virtual]

TIME precision of the item: 0..6

Reimplemented in Item_temporal_func.

Field * Item::tmp_table_field_from_field_type	(	TABLE *	table,
		bool	fixed_length
	)

Create a field based on field_type of argument.

For now, this is only used to create a field for IFNULL(x,something) and time functions

Return values:

NULL	error
\::	Created field

Item * Item::transform	(	Item_transformer	transformer,
		uchar *	arg
	)		`[virtual]`

Traverse item tree possibly transforming it (replacing items).

This function is designed to ease transformation of Item trees. Re-execution note: every such transformation is registered for rollback by THD::change_item_tree() and is rolled back at the end of execution by THD::rollback_item_tree_changes().

Therefore:

this function can not be used at prepared statement prepare (in particular, in fix_fields!), as only permanent transformation of Item trees are allowed at prepare.
the transformer function shall allocate new Items in execution memory root (thd->mem_root) and not anywhere else: allocated items will be gone in the end of execution.

If you don't need to transform an item tree, but only traverse it, please use Item::walk() instead.

Parameters:

transformer	functor that performs transformation of a subtree
arg	opaque argument passed to the functor

Returns:: Returns pointer to the new subtree root. THD::change_item_tree() should be called for it if transformation took place, i.e. if a pointer to newly allocated item is returned.

Reimplemented in Item_default_value, Item_ref, Item_equal, Item_cond, Item_func_make_set, Item_in_optimizer, Item_func, and Item_row.

bool Item::val_bool ( ) [virtual]

Todo:: Make this functions class dependent

Reimplemented in Item_ref_null_helper, Item_direct_ref, Item_ref, Item_in_subselect, Item_exists_subselect, Item_singlerow_subselect, and Item_func_truth.

longlong Item::val_date_temporal ( ) [virtual]

Return date value of item in packed longlong format.

Reimplemented in Item_cache_datetime, Item_cache_int, Item_time_with_ref, Item_datetime_with_ref, Item_ref_null_helper, Item_direct_ref, Item_ref, Item_temporal, Item_null, Item_field, Item_func_now, Item_func_curdate, Item_sum_hybrid, Item_datetime_literal, Item_date_literal, Item_datetime_func, and Item_date_func.

virtual longlong Item::val_date_temporal_result ( ) [inline, virtual]

Get date value in packed longlong format. NULL is converted to 0.

Reimplemented in Item_field.

longlong Item::val_temporal_by_field_type ( ) [inline]

Return date or time value of item in packed longlong format, depending on item field type.

longlong Item::val_temporal_with_round	(	enum_field_types	type,
		uint8	dec
	)

Get date or time value in packed longlong format. Before conversion from MYSQL_TIME to packed format, the MYSQL_TIME value is rounded to "dec" fractional digits.

longlong Item::val_time_temporal ( ) [virtual]

Return time value of item in packed longlong format.

Reimplemented in Item_cache_datetime, Item_cache_int, Item_time_with_ref, Item_datetime_with_ref, Item_ref_null_helper, Item_direct_ref, Item_ref, Item_temporal, Item_null, Item_field, Item_sum_hybrid, Item_func_curtime, Item_time_literal, and Item_time_func.

virtual longlong Item::val_time_temporal_result ( ) [inline, virtual]

Get time value in packed longlong format. NULL is converted to 0.

Reimplemented in Item_field.

Member Data Documentation

int Item::marker

This member has several successive meanings, depending on the phase we're in:

during field resolution: it contains the index, in the "all_fields" list, of the expression to which this field belongs; or a special constant UNDEF_POS; see st_select_lex::cur_pos_in_all_fields and match_exprs_for_only_full_group_by().
when attaching conditions to tables: it says whether some condition needs to be attached or can be omitted (for example because it is already implemented by 'ref' access)
when pushing index conditions: it says whether a condition uses only indexed columns
when creating an internal temporary table: it says how to store BIT fields
when we change DISTINCT to GROUP BY: it is used for book-keeping of fields.

Item* Item::next

Intrusive list pointer for free list. If not null, points to the next Item on some Query_arena's free list. For instance, stored procedures have their own Query_arena's.

See also:: Query_arena::free_list

Reimplemented in Item_sum.

bool Item::tables_locked_cache [protected]

This variable is a cache of 'Needed tables are locked'. True if either 'No tables locks is needed' or 'Needed tables are locked'. If tables are used, then it will be set to current_thd->lex->is_query_tables_locked().

It is used when checking const_item()/can_be_evaluated_now().

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

item.h
item.cc

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation