#include <item.h>

Inheritance diagram for Item_default_value:

Public Member Functions
	Item_default_value (const POS &pos, Item *a=nullptr)

bool	do_itemize (Parse_context pc, Item *res) override
	The core function that does the actual itemization. More...

enum Type	type () const override

bool	eq (const Item *item) const override
	Compare this item with another item for equality. More...

bool	fix_fields (THD , Item *) override
	Resolve the name of a column reference. More...

void	bind_fields () override
	Bind objects from the current execution context to field objects in item trees. More...

void	cleanup () override
	Called for every Item after use (preparation and execution). More...

void	print (const THD thd, String str, enum_query_type query_type) const override
	This method is used for to: More...

table_map	used_tables () const override

Item *	get_tmp_table_item (THD *thd) override
	If an Item is materialized in a temporary table, a different Item may have to be used in the part of the query that runs after the materialization. More...

bool	collect_item_field_or_view_ref_processor (uchar *arg) override
	Collects fields and view references that have the qualifying table in the specified query block. More...

Item *	replace_item_field (uchar *) override
	If this default value is the target of replacement, replace it with the info object's item or, if the item is found inside a subquery, the target is an outer reference, so we create a new `Item_field`, mark it accordingly and replace with that instead. More...

bool	check_column_privileges (uchar *) override
	Check privileges of base table column. More...

bool	walk (Item_processor processor, enum_walk walk, uchar *args) override
	Traverses a tree of Items in prefix and/or postfix order. More...

bool	check_gcol_depend_default_processor (uchar *args) override
	Check if a generated expression depends on DEFAULT function with specific column name as argument. More...

Item *	transform (Item_transformer transformer, uchar *args) override
	Perform a generic transformation of the Item tree, by adding zero or more additional Item objects to it. More...

Item *	argument () const

Public Member Functions inherited from Item_field
Item_multi_eq *	multi_equality () const

void	set_item_equal_all_join_nests (Item_multi_eq *item_equal)

	Item_field (Name_resolution_context context_arg, const char db_arg, const char table_name_arg, const char field_name_arg)
	Constructor used for internal information queries. More...

	Item_field (const POS &pos, const char db_arg, const char table_name_arg, const char *field_name_arg)
	Used from parser to construct column references. More...

	Item_field (THD thd, Item_field item)
	Used to create a copy (clone) of another Item_field. More...

	Item_field (THD thd, Name_resolution_context context_arg, Field *field)
	Constructor used inside setup_wild(). More...

	Item_field (Field *field)
	Create column reference based on a table field. More...

double	val_real () override

longlong	val_int () override

longlong	val_time_temporal () override
	Return time value of item in packed longlong format. More...

longlong	val_date_temporal () override
	Return date value of item in packed longlong format. More...

longlong	val_time_temporal_at_utc () override

longlong	val_date_temporal_at_utc () override

my_decimal *	val_decimal (my_decimal *) override

String *	val_str (String *) override

bool	val_json (Json_wrapper *result) override
	Get a JSON value from an Item. More...

bool	send (Protocol protocol, String str_arg) override
	This is only called from items that is not of type item_field. More...

void	reset_field (Field *f)
	Reset this item to point to a field from the new temporary table. More...

void	make_field (Send_field *tmp_field) override

void	save_org_in_field (Field *field) override
	Set a field's value from a item. More...

Item_result	result_type () const override

Item_result	numeric_context_result_type () const override
	Result type when an item appear in a numeric context. More...

TYPELIB *	get_typelib () const override
	Get the typelib information for an item of type set or enum. More...

Item_result	cast_to_int_type () const override

enum_monotonicity_info	get_monotonicity_info () const override

longlong	val_int_endpoint (bool left_endp, bool *incl_endp) override

void	set_result_field (Field *field_arg) override

Field *	get_tmp_table_field () override
	If this Item is being materialized into a temporary table, returns the field that is being materialized into. More...

Field *	tmp_table_field (TABLE *) override

void	set_base_item_field (const Item_field *item)

const Item_field *	base_item_field () const

bool	get_date (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) override

bool	get_time (MYSQL_TIME *ltime) override

bool	get_timeval (my_timeval tm, int warnings) override
	Get timestamp in "struct timeval" format. More...

bool	is_null () override
	The method allows to determine nullness of a complex expression without fully evaluating it, instead of calling val*() then checking null_value. More...

bool	collect_item_field_processor (uchar *arg) override
	Store the pointer to this item field into a list if not already there. More...

bool	collect_item_field_or_ref_processor (uchar *arg) override
	When collecting information about columns when transforming correlated scalar subqueries using derived tables, we need to decide which duplicates, if any, to retain: More...

bool	collect_outer_field_processor (uchar *arg) override

bool	add_field_to_set_processor (uchar *arg) override
	Item::walk function. More...

bool	add_field_to_cond_set_processor (uchar *) override
	Item::walk function. More...

bool	remove_column_from_bitmap (uchar *arg) override
	Visitor interface for removing all column expressions (Item_field) in this expression tree from a bitmap. More...

bool	find_item_in_field_list_processor (uchar *arg) override
	Check if an Item_field references some field from a list of fields. More...

bool	find_field_processor (uchar *arg) override
	Is this an Item_field which references the given Field argument? More...

bool	check_function_as_value_generator (uchar *args) override
	Check if this item is allowed for a virtual column or inside a default expression. More...

bool	mark_field_in_map (uchar *arg) override
	Mark underlying field in read or write map of a table. More...

bool	used_tables_for_level (uchar *arg) override
	Return used table information for the specified query block (level). More...

bool	check_partition_func_processor (uchar *) override
	Check if a partition function is allowed. More...

bool	is_valid_for_pushdown (uchar *arg) override
	Check if all the columns present in this expression are from the derived table. More...

bool	check_column_in_window_functions (uchar *arg) override
	Check if this column is found in PARTITION clause of all the window functions. More...

bool	check_column_in_group_by (uchar *arg) override
	Check if this column is found in GROUP BY. More...

Item *	replace_with_derived_expr (uchar *arg) override
	Assuming this expression is part of a condition that would be pushed to the WHERE clause of a materialized derived table, replace, in this expression, each derived table's column with a clone of the expression lying under it in the derived table's definition. More...

Item *	replace_with_derived_expr_ref (uchar *arg) override
	Assuming this expression is part of a condition that would be pushed to the HAVING clause of a materialized derived table, replace, in this expression, each derived table's column with a reference to the expression lying under it in the derived table's definition. More...

void	reset_field ()
	Reset all aspect of a field object, so that it can be re-resolved. More...

Item_multi_eq *	find_multi_equality (COND_EQUAL *cond_equal) const
	Find a field among specified multiple equalities. More...

bool	subst_argument_checker (uchar **arg) override
	Check whether a field can be substituted by an equal item. More...

Item *	equal_fields_propagator (uchar *arg) override
	If field matches a multiple equality, set a pointer to that object in the field. More...

bool	disable_constant_propagation (uchar *) override

Item *	replace_equal_field (uchar *) override
	Replace an Item_field for an equal Item_field that evaluated earlier (if any). More...

uint32	max_disp_length ()

Item_field *	field_for_view_update () override

bool	fix_outer_field (THD thd, Field field, Item_ident ref_field, bool complete)
	Resolve the name of a column that may be an outer reference. More...

Item *	update_value_transformer (uchar *select_arg) override
	Add the field to the select list and substitute it for the reference to the field. More...

bool	is_outer_field () const override

Field::geometry_type	get_geometry_type () const override

const CHARSET_INFO *	charset_for_protocol (void) override

void	dbug_print () const

float	get_filtering_effect (THD thd, table_map filter_for_table, table_map read_tables, const MY_BITMAP fields_to_ignore, double rows_in_table) override
	Calculate condition filtering effect for "WHERE field", which implicitly means "WHERE field <> 0". More...

float	get_cond_filter_default_probability (double max_distinct_values, float default_filter) const
	Returns the probability for the predicate "col OP <val>" to be true for a row in the case where no index statistics or range estimates are available for 'col'. More...

bool	alias_name_used () const override

bool	repoint_const_outer_ref (uchar *arg) override
	If this object is the real_item of an Item_ref, repoint the result_field to field. More...

bool	returns_array () const override
	Whether the item returns array of its data type. More...

void	set_can_use_prefix_key () override

bool	replace_field_processor (uchar *arg) override
	A processor that replaces any Fields with a Create_field_wrapper. More...

bool	strip_db_table_name_processor (uchar *) override
	Generated fields don't need db/table names. More...

virtual bool	is_asterisk () const
	Checks if the current object represents an asterisk select list item. More...

bool	protected_by_any_value () const
	See `m_protected_by_any_value`. More...

void	compute_cost (CostOfItem *root_cost) const override
	Compute the cost of evaluating this Item. More...

Public Member Functions inherited from Item_ident
	Item_ident (Name_resolution_context context_arg, const char db_name_arg, const char table_name_arg, const char field_name_arg)

	Item_ident (const POS &pos, const char db_name_arg, const char table_name_arg, const char *field_name_arg)

	Item_ident (THD thd, Item_ident item)
	Constructor used by Item_field & Item_*_ref (see Item comment) More...

const char *	full_name () const override

void	set_orignal_db_name (const char *name_arg)

void	set_original_table_name (const char *name_arg)

void	set_original_field_name (const char *name_arg)

const char *	original_db_name () const

const char *	original_table_name () const

const char *	original_field_name () const

bool	aggregate_check_distinct (uchar *arg) override

bool	aggregate_check_group (uchar *arg) override

Bool3	local_column (const Query_block *sl) const override
	Tells if this is a column of a table whose qualifying query block is 'sl'. More...

bool	change_context_processor (uchar *arg) override

bool	is_alias_of_expr () const

void	set_alias_of_expr ()
	Marks that this Item's name is alias of SELECT expression. More...

bool	update_depended_from (uchar *) override

bool	is_strong_side_column_not_in_fd (uchar *arg) override

bool	is_column_not_in_fd (uchar *arg) override

Public Member Functions inherited from Item
	Item (const Item &)=delete

void	operator= (Item &)=delete

	Item ()
	Item constructor for general use. More...

	Item (THD thd, const Item item)
	Constructor used by Item_field, Item_ref & aggregate functions. More...

	Item (const POS &)
	Parse-time context-independent constructor. More...

	~Item () override=default

virtual bool	itemize (Parse_context pc, Item *res) final
	The same as contextualize() but with additional parameter. More...

void	rename (char *new_name)
	rename item (used for views, cleanup() return original name). More...

void	init_make_field (Send_field *tmp_field, enum enum_field_types type)

virtual void	notify_removal ()
	Called when an item has been removed, can be used to notify external objects about the removal, e.g subquery predicates that are part of the sj_candidates container. More...

virtual Field *	make_string_field (TABLE *table) const
	Create a field to hold a string value from an item. More...

void	quick_fix_field ()

virtual bool	propagate_type (THD *thd, const Type_properties &type)
	Propagate data type specifications into parameters and user variables. More...

bool	propagate_type (THD *thd, enum_field_types def=MYSQL_TYPE_VARCHAR, bool pin=false, bool inherit=false)
	Wrapper for easier calling of propagate_type(const Type_properties &). More...

virtual void	mark_json_as_scalar ()
	For Items with data type JSON, mark that a string argument is treated as a scalar JSON value. More...

virtual std::optional< ContainedSubquery >	get_contained_subquery (const Query_block *outer_query_block)
	If this item represents a IN/ALL/ANY/comparison_operator subquery, return that (along with data on how it will be executed). More...

type_conversion_status	save_in_field_no_warnings (Field *field, bool no_conversions)
	Save the item into a field but do not emit any warnings. More...

type_conversion_status	save_in_field (Field *field, bool no_conversions)
	Save a temporal value in packed longlong format into a Field. More...

void	save_in_field_no_error_check (Field *field, bool no_conversions)
	A slightly faster value of save_in_field() that returns no error value (you will need to check thd->is_error() yourself), and does not support saving into hidden fields for functional indexes. More...

bool	evaluate (THD thd, String str)
	Evaluate scalar item, possibly using the supplied buffer. More...

const Item *	unwrap_for_eq () const
	Unwrap an Item argument so that Item::eq() can see the "real" item, and not just the wrapper. More...

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

virtual void	set_data_type_inherited ()
	Set data type for item as inherited. More...

virtual void	pin_data_type ()
	Pin the data type for the item. More...

enum_field_types	data_type () const
	Retrieve the derived data type of the Item. More...

virtual enum_field_types	actual_data_type () const
	Retrieve actual data type for an item. More...

virtual enum_field_types	default_data_type () const
	Get the default data (output) type for the specific item. More...

void	set_data_type (enum_field_types data_type)
	Set the data type of the current Item. More...

void	set_data_type_null ()

void	set_data_type_bool ()

void	set_data_type_int (enum_field_types type, bool unsigned_prop, uint32 max_width)
	Set the data type of the Item to be a specific integer type. More...

void	set_data_type_longlong ()
	Set the data type of the Item to be longlong. More...

void	set_data_type_decimal (uint8 precision, uint8 scale)
	Set the data type of the Item to be decimal. More...

void	set_data_type_double ()
	Set the data type of the Item to be double precision floating point. More...

void	set_data_type_float ()
	Set the data type of the Item to be single precision floating point. More...

void	set_data_type_string (uint32 max_l)
	Set the Item to be variable length string. More...

void	set_data_type_string (ulonglong max_char_length_arg)
	Set the Item to be variable length string. More...

void	set_data_type_string (uint32 max_l, const CHARSET_INFO *cs)
	Set the Item to be variable length string. More...

void	set_data_type_string (uint32 max_l, const DTCollation &coll)
	Set the Item to be variable length string. More...

void	set_data_type_char (uint32 max_l)
	Set the Item to be fixed length string. More...

void	set_data_type_char (uint32 max_l, const CHARSET_INFO *cs)
	Set the Item to be fixed length string. More...

void	set_data_type_blob (enum_field_types type, uint32 max_l)
	Set the Item to be of BLOB type. More...

void	set_data_type_date ()
	Set all type properties for Item of DATE type. More...

void	set_data_type_time (uint8 fsp)
	Set all type properties for Item of TIME type. More...

void	set_data_type_datetime (uint8 fsp)
	Set all properties for Item of DATETIME type. More...

void	set_data_type_timestamp (uint8 fsp)
	Set all properties for Item of TIMESTAMP type. More...

void	set_data_type_vector (uint32 max_l)
	Set the data type of the Item to be VECTOR. More...

void	set_data_type_geometry ()
	Set the data type of the Item to be GEOMETRY. More...

void	set_data_type_json ()
	Set the data type of the Item to be JSON. More...

void	set_data_type_year ()
	Set the data type of the Item to be YEAR. More...

void	set_data_type_bit (uint32 max_bits)
	Set the data type of the Item to be bit. More...

void	set_data_type_from_item (const Item *item)
	Set data type properties of the item from the properties of another item. More...

bool	aggregate_type (const char name, Item *items, uint count)
	Aggregates data types from array of items into current item. More...

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

longlong	int_sort_key ()
	Produces a key suitable for filesort. More...

longlong	val_temporal_with_round (enum_field_types type, uint8 dec)
	Get date or time value in packed longlong format. More...

ulonglong	val_uint ()

virtual String *	val_str_ascii (String *str)

virtual bool	val_bool ()

bool	error_json ()
	Get the value to return from val_json() in case of errors. More...

bool	get_date_from_non_temporal (MYSQL_TIME *ltime, my_time_flags_t fuzzydate)
	Convert a non-temporal type to date. More...

bool	get_time_from_non_temporal (MYSQL_TIME *ltime)
	Convert a non-temporal type to time. More...

my_decimal *	error_decimal (my_decimal *decimal_value)
	Get the value to return from val_decimal() in case of errors. More...

String *	error_str ()
	Get the value to return from val_str() in case of errors. More...

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 table_map	not_null_tables () const
	Return table map of tables that can't be NULL tables (tables that are used in a context where if they would contain a NULL row generated by a LEFT or RIGHT join, the item would not be true). More...

virtual bool	basic_const_item () const
	Returns true if this is a simple constant item like an integer, not a constant expression. More...

bool	may_eval_const_item (const THD *thd) const

virtual Item *	clone_item () const

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 ()
	TIME precision of the item: 0..6. More...

virtual uint	datetime_precision ()
	DATETIME precision of the item: 0..6. More...

bool	const_item () const
	Returns true if item is constant, regardless of query evaluation state. More...

bool	const_for_execution () const
	Returns true if item is constant during one query execution. More...

bool	may_evaluate_const (const THD *thd) const
	Return true if this is a const item that may be evaluated in the current phase of statement processing. More...

bool	is_non_deterministic () const

bool	is_outer_reference () const

void	print_item_w_name (const THD thd, String , enum_query_type query_type) const

void	print_for_order (const THD thd, String str, enum_query_type query_type, const char *used_alias) const
	Prints the item when it's part of ORDER BY and GROUP BY. More...

virtual void	update_used_tables ()
	Updates used tables, not null tables information and accumulates properties up the item tree, cf. More...

virtual bool	split_sum_func (THD , Ref_item_array, mem_root_deque< Item > *)

bool	split_sum_func2 (THD thd, Ref_item_array ref_item_array, mem_root_deque< Item > fields, Item *ref, bool skip_registered)

bool	update_null_value ()
	Make sure the null_value member has a correct value. More...

virtual void	apply_is_true ()
	Apply the IS TRUE truth property, meaning that an UNKNOWN result and a FALSE result are treated the same. More...

virtual bool	is_result_field () const

virtual Field *	get_result_field () const

virtual bool	is_bool_func () const

virtual void	no_rows_in_result ()

virtual Item *	copy_or_same (THD *)

virtual Item *	copy_andor_structure (THD *)

virtual Item *	real_item ()

virtual const Item *	real_item () const

virtual const CHARSET_INFO *	compare_collation () const

template<class T >
auto	walk_helper_thunk (uchar *arg)

template<class T >
auto	analyze_helper_thunk (uchar **arg)
	See CompileItem. More...

virtual Item *	compile (Item_analyzer analyzer, uchar *arg_p, Item_transformer transformer, uchar arg_t)
	Perform a generic "compilation" of the Item tree, ie transform the Item tree by adding zero or more Item objects to it. More...

virtual void	traverse_cond (Cond_traverser traverser, void *arg, traverse_order)

virtual bool	intro_version (uchar *)

bool	cleanup_processor (uchar *)
	cleanup() item if it is resolved ('fixed'). More...

virtual bool	visitor_processor (uchar *arg)
	A processor to handle the select lex visitor framework. More...

virtual bool	find_item_processor (uchar *arg)

virtual bool	is_non_const_over_literals (uchar *)

virtual bool	cast_incompatible_args (uchar *)
	Wrap incompatible arguments in CAST nodes to the expected data types. More...

virtual bool	reset_wf_state (uchar *arg)
	Reset execution state for such window function types as determined by arg. More...

virtual bool	inform_item_in_cond_of_tab (uchar *)

virtual bool	clean_up_after_removal (uchar *arg)
	Clean up after removing the item from the item tree. More...

virtual bool	collect_scalar_subqueries (uchar *)

virtual bool	collect_grouped_aggregates (uchar *)

virtual bool	collect_subqueries (uchar *)

virtual bool	has_aggregate_ref_in_group_by (uchar *)
	Check if an aggregate is referenced from within the GROUP BY clause of the query block in which it is aggregated. More...

bool	visit_all_analyzer (uchar **)

virtual bool	cache_const_expr_analyzer (uchar **cache_item)
	Check if an item is a constant one and can be cached. More...

Item *	cache_const_expr_transformer (uchar *item)
	Cache item if needed. More...

virtual bool	equality_substitution_analyzer (uchar **)

virtual Item *	equality_substitution_transformer (uchar *)

virtual bool	explain_subquery_checker (uchar **)

virtual Item *	explain_subquery_propagator (uchar *)

virtual bool	replace_equal_field_checker (uchar **)

virtual bool	check_valid_arguments_processor (uchar *)

virtual Item *	replace_view_refs_with_clone (uchar *arg)
	Assuming this expression is part of a condition that would be pushed to a materialized derived table, replace, in this expression, each view reference with a clone of the expression in merged derived table's definition. More...

virtual Item *	this_item ()

virtual const Item *	this_item () const

virtual Item **	this_item_addr (THD , Item *addr_arg)

virtual uint	cols () const

virtual Item *	element_index (uint)

virtual Item **	addr (uint)

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) const
	Create a field based on field_type of argument. More...

virtual Item *	truth_transformer (THD *thd, Bool_test test)
	Informs an item that it is wrapped in a truth test, in case it wants to transforms itself to implement this test by itself. More...

virtual Item *	replace_scalar_subquery (uchar *)
	When walking the item tree seeing an Item_singlerow_subselect matching a target, replace it with a substitute field used when transforming scalar subqueries into derived tables. More...

virtual Item *	replace_func_call (uchar *)

virtual Item *	replace_item_view_ref (uchar *)

virtual Item *	replace_aggregate (uchar *)

virtual Item *	replace_outer_ref (uchar *)

virtual bool	update_aggr_refs (uchar *)
	A walker processor overridden by Item_aggregate_ref, q.v. More...

Item *	convert_charset (THD thd, const CHARSET_INFO tocs, bool ignore_errors=false)
	Convert constant string in this object into the specified character set. More...

void	delete_self ()
	Delete this item. More...

virtual bool	is_splocal () const

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
	Check whether this and the given item has compatible comparison context. More...

String *	check_well_formed_result (String *str, bool send_error, bool truncate)
	Verifies that the input string is well-formed according to its character set. More...

bool	eq_by_collation (Item item, const CHARSET_INFO cs)
	Compare two items using a given collation. More...

CostOfItem	cost () const

uint32	max_char_length () const

uint32	max_char_length (const CHARSET_INFO *cs) const

void	fix_char_length (uint32 max_char_length_arg)

bool	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. More...

uint	reference_count () const

void	increment_ref_count ()
	Increment reference count. More...

uint	decrement_ref_count ()
	Decrement reference count. More...

bool	has_subquery () const

bool	has_stored_program () const

bool	has_aggregation () const

void	set_aggregation ()
	Set the "has aggregation" property. More...

void	reset_aggregation ()
	Reset the "has aggregation" property. More...

bool	has_wf () const

void	set_wf ()
	Set the "has window function" property. More...

bool	has_grouping_set_dep () const

void	set_group_by_modifier ()
	Set the property: this item (tree) contains a reference to a GROUP BY modifier (such as ROLLUP) More...

bool	has_grouping_func () const

void	set_grouping_func ()
	Set the property: this item is a call to GROUPING. More...

virtual bool	created_by_in2exists () const
	Whether this Item was created by the IN->EXISTS subquery transformation. More...

void	mark_subqueries_optimized_away ()

virtual bool	gc_subst_analyzer (uchar **)
	Analyzer function for GC substitution. More...

virtual Item *	gc_subst_transformer (uchar *)
	Transformer function for GC substitution. More...

bool	can_be_substituted_for_gc (bool array=false) const
	Check if this item is of a type that is eligible for GC substitution. More...

void	aggregate_float_properties (enum_field_types type, Item **items, uint nitems)
	Set max_length and decimals of function if function is floating point and result length/precision depends on argument ones. More...

void	aggregate_decimal_properties (Item **items, uint nitems)
	Set data type, precision and scale of item of type decimal from list of items. More...

void	aggregate_temporal_properties (enum_field_types type, Item **items, uint nitems)
	Set data type and fractional seconds precision for temporal functions. More...

bool	aggregate_string_properties (enum_field_types type, const char name, Item *items, uint nitems)
	Aggregate string properties (character set, collation and maximum length) for string function. More...

void	aggregate_bit_properties (Item **items, uint nitems)
	Set data type and properties of a BIT column. More...

bool	is_abandoned () const

bool	is_nullable () const

void	set_nullable (bool nullable)

virtual bool	supports_partial_update (const Field_json *field) const
	Check if this expression can be used for partial update of a given JSON column. More...

virtual void	allow_array_cast ()
	A helper function to ensure proper usage of CAST(. More...

Public Member Functions inherited from Parse_tree_node_tmpl< Context >
virtual	~Parse_tree_node_tmpl ()=default

bool	is_contextualized () const

virtual bool	contextualize (Context *pc) final

void	error (Context *pc, const POS &pos) const
	syntax_error() function replacement for deferred reporting of syntax errors More...

void	error (Context pc, const POS &pos, const char msg) const
	syntax_error() function replacement for deferred reporting of syntax errors More...

void	errorf (Context pc, const POS &pos, const char format,...) const
	syntax_error() function replacement for deferred reporting of syntax errors More...

Protected Member Functions
type_conversion_status	save_in_field_inner (Field *field, bool no_conversions) override
	Helper function which does all of the work for save_in_field(Field*, bool), except some error checking common to all subclasses, which is performed by save_in_field() itself. More...

Protected Member Functions inherited from Item_field
void	set_field (Field *field)

void	fix_after_pullout (Query_block parent_query_block, Query_block removed_query_block) override
	Fix after tables have been moved from one query_block level to the parent level, e.g by semijoin conversion. More...

Protected Member Functions inherited from Item_ident
void	print (const THD thd, String str, enum_query_type query_type, const char db_name_arg, const char table_name_arg) const
	Function to print column name for a table. More...

Protected Member Functions inherited from Item
String *	make_empty_result ()
	Sets the result value of the function an empty string, using the current character set. More...

bool	skip_itemize (Item **res)
	Helper function to skip itemize() for grammar-allocated items. More...

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 ()

longlong	val_int_from_string ()

double	val_real_from_decimal ()

double	val_real_from_string ()

bool	error_bool ()
	Get the value to return from val_bool() in case of errors. More...

int	error_int ()
	Get the value to return from val_int() in case of errors. More...

double	error_real ()
	Get the value to return from val_real() in case of errors. More...

bool	error_date ()
	Get the value to return from get_date() in case of errors. More...

bool	error_time ()
	Get the value to return from get_time() in case of errors. More...

String *	null_return_str ()
	Gets the value to return from val_str() when returning a NULL value. More...

bool	get_date_from_string (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_str() to date in MYSQL_TIME. More...

bool	get_date_from_real (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_real() to date in MYSQL_TIME. More...

bool	get_date_from_decimal (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_decimal() to date in MYSQL_TIME. More...

bool	get_date_from_int (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_int() to date in MYSQL_TIME. More...

bool	get_date_from_time (MYSQL_TIME *ltime)
	Convert get_time() from time to date in MYSQL_TIME. More...

bool	get_date_from_numeric (MYSQL_TIME *ltime, my_time_flags_t fuzzydate)
	Convert a numeric type to date. More...

bool	get_time_from_string (MYSQL_TIME *ltime)
	Convert val_str() to time in MYSQL_TIME. More...

bool	get_time_from_real (MYSQL_TIME *ltime)
	Convert val_real() to time in MYSQL_TIME. More...

bool	get_time_from_decimal (MYSQL_TIME *ltime)
	Convert val_decimal() to time in MYSQL_TIME. More...

bool	get_time_from_int (MYSQL_TIME *ltime)
	Convert val_int() to time in MYSQL_TIME. More...

bool	get_time_from_date (MYSQL_TIME *ltime)
	Convert date to time. More...

bool	get_time_from_datetime (MYSQL_TIME *ltime)
	Convert datetime to time. More...

bool	get_time_from_numeric (MYSQL_TIME *ltime)
	Convert a numeric type to time. More...

void	set_accum_properties (const Item *item)
	Set accumulated properties for an Item. More...

void	add_accum_properties (const Item *item)
	Add more accumulated properties to an Item. More...

void	set_subquery ()
	Set the "has subquery" property. More...

void	set_stored_program ()
	Set the "has stored program" property. More...

Protected Member Functions inherited from Parse_tree_node_tmpl< Context >
	Parse_tree_node_tmpl ()=delete

	Parse_tree_node_tmpl (const POS &pos)

	Parse_tree_node_tmpl (const POS &start_pos, const POS &end_pos)

bool	begin_parse_tree (Show_parse_tree *tree)

bool	end_parse_tree (Show_parse_tree *tree)

virtual bool	do_contextualize (Context *pc)
	Do all context-sensitive things and mark the node as contextualized. More...

virtual void	add_json_info (Json_object *json_obj)
	Add all the node-specific json fields. More...

Private Types
typedef Item_field	super

Private Attributes
Item *	arg
	The argument for this function. More...

uchar *	m_rowbuffer_saved {nullptr}
	Pointer to row buffer that was used to calculate field value offset. More...

Additional Inherited Members
Public Types inherited from Item
enum	Type { INVALID_ITEM , FIELD_ITEM , FUNC_ITEM , SUM_FUNC_ITEM , AGGR_FIELD_ITEM , STRING_ITEM , INT_ITEM , DECIMAL_ITEM , REAL_ITEM , NULL_ITEM , HEX_BIN_ITEM , DEFAULT_VALUE_ITEM , COND_ITEM , REF_ITEM , INSERT_VALUE_ITEM , SUBQUERY_ITEM , ROW_ITEM , CACHE_ITEM , TYPE_HOLDER_ITEM , PARAM_ITEM , ROUTINE_FIELD_ITEM , TRIGGER_FIELD_ITEM , XPATH_NODESET_ITEM , VALUES_COLUMN_ITEM , NAME_CONST_ITEM }

enum	cond_result { COND_UNDEF , COND_OK , COND_TRUE , COND_FALSE }

enum	traverse_order { POSTFIX , PREFIX }

enum	enum_const_item_cache { CACHE_NONE = 0 , CACHE_JSON_VALUE , CACHE_JSON_ATOM }
	How to cache constant JSON data. More...

enum	Bool_test { BOOL_IS_TRUE = 0x00 , BOOL_IS_FALSE = 0x01 , BOOL_IS_UNKNOWN = 0x02 , BOOL_NOT_TRUE = 0x03 , BOOL_NOT_FALSE = 0x04 , BOOL_NOT_UNKNOWN = 0x05 , BOOL_IDENTITY = 0x06 , BOOL_NEGATED = 0x07 , BOOL_ALWAYS_TRUE = 0x08 , BOOL_ALWAYS_FALSE = 0x09 }
	< Modifier for result transformation More...

enum	item_marker { MARKER_NONE = 0 , MARKER_IMPLICIT_NE_ZERO = 1 , MARKER_CONST_PROPAG = 2 , MARKER_BIT = 4 , MARKER_FUNC_DEP_NOT_NULL = 5 , MARKER_DISTINCT_GROUP = 6 , MARKER_COND_DERIVED_TABLE = 7 , MARKER_TRAVERSAL = 8 , MARKER_ICP_COND_USES_INDEX_ONLY = 10 }
	< Values for member 'marker' More...

Public Types inherited from Parse_tree_node_tmpl< Context >
typedef Context	context_t

Static Public Member Functions inherited from Item
static void *	operator new (size_t size) noexcept

static void *	operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &arg=std::nothrow) noexcept

static void	operator delete (void *ptr, size_t size)

static void	operator delete (void , MEM_ROOT , const std::nothrow_t &) noexcept

static enum_field_types	result_to_type (Item_result result)

static Item_result	type_to_result (enum_field_types type)

static enum_field_types	type_for_variable (enum_field_types src_type)
	Provide data type for a user or system variable, based on the type of the item that is assigned to the variable. More...

static enum_field_types	string_field_type (uint32 max_bytes)
	Determine correct string field type, based on string length. More...

static const CHARSET_INFO *	default_charset ()

Static Public Member Functions inherited from Parse_tree_node_tmpl< Context >
static void *	operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &arg=std::nothrow) noexcept

static void	operator delete (void *ptr, size_t size)

static void	operator delete (void , MEM_ROOT , const std::nothrow_t &) noexcept

Public Attributes inherited from Item_field
Field *	field {nullptr}
	Source field. More...

uint16	field_index {NO_FIELD_INDEX}
	Index for this field in table->field array. More...

Item_multi_eq *	item_equal_all_join_nests {nullptr}

bool	no_constant_propagation {false}
	If true, the optimizer's constant propagation will not replace this item with an equal constant. More...

Access_bitmask	have_privileges {0}

bool	any_privileges {false}

bool	can_use_prefix_key {false}

Public Attributes inherited from Item_ident
Name_resolution_context *	context
	For regularly resolved column references, 'context' points to a name resolution context object belonging to the query block which simply contains the reference. More...

const char *	db_name
	Schema name of the base table or view the column is part of. More...

const char *	table_name
	If column is from a non-aliased base table or view, name of base table or view. More...

const char *	field_name
	If column is aliased, the column alias name. More...

Table_ref *	m_table_ref {nullptr}
	Points to the Table_ref object of the table or view that the column or reference is resolved against (only valid after resolving). More...

Query_block *	depended_from {nullptr}
	For a column or reference that is an outer reference, depended_from points to the qualifying query block, otherwise it is NULL (only valid after resolving). More...

Public Attributes inherited from Item
Item *	next_free
	Intrusive list pointer for free list. More...

DTCollation	collation
	Character set and collation properties assigned for this Item. More...

Item_name_string	item_name
	Name from query. More...

Item_name_string	orig_name
	Original item name (if it was renamed) More...

uint32	max_length
	Maximum length of result of evaluating this item, in number of bytes. More...

item_marker	marker
	This member has several successive meanings, depending on the phase we're in (. More...

Item_result	cmp_context
	Comparison context. More...

bool	fixed
	True if item has been resolved. More...

uint8	decimals
	Number of decimals in result when evaluating this item. More...

bool	null_value
	True if item is null. More...

bool	unsigned_flag

bool	m_is_window_function
	True if item represents window func. More...

bool	hidden {false}
	If the item is in a SELECT list (Query_block::fields) and hidden is true, the item wasn't actually in the list as given by the user (it was added by the optimizer, to e.g. More...

bool	m_in_check_constraint_exec_ctx {false}
	True if item is a top most element in the expression being evaluated for a check constraint. More...

Public Attributes inherited from Parse_tree_node_tmpl< Context >
POS	m_pos

Static Protected Member Functions inherited from Item
static bool	bit_func_returns_binary (const Item a, const Item b)

static bool	mark_field_in_map (Mark_field mark_field, Field field)
	Helper function for mark_field_in_map(uchar *arg). More...

Protected Attributes inherited from Item_ident
const char *	m_orig_db_name
	The fields m_orig_db_name, m_orig_table_name and m_orig_field_name are maintained so that we can provide information about the origin of a column that may have been renamed within the query, e.g. More...

const char *	m_orig_table_name
	Names the original table that is the source of the field. More...

const char *	m_orig_field_name
	Names the field in the source base table. More...

bool	m_alias_of_expr
	if this Item's name is alias of SELECT expression More...

Protected Attributes inherited from Item
String	str_value
	str_values's main purpose is to cache the value in save_in_field More...

uint8	m_accum_properties

Static Protected Attributes inherited from Item
static constexpr uint8	PROP_SUBQUERY = 0x01
	Set of properties that are calculated by accumulation from underlying items. More...

static constexpr uint8	PROP_STORED_PROGRAM = 0x02

static constexpr uint8	PROP_AGGREGATION = 0x04

static constexpr uint8	PROP_WINDOW_FUNCTION = 0x08

static constexpr uint8	PROP_HAS_GROUPING_SET_DEP = 0x10
	Set if the item or one or more of the underlying items contains a GROUP BY modifier (such as ROLLUP). More...

static constexpr uint8	PROP_GROUPING_FUNC = 0x20
	Set if the item or one or more of the underlying items is a GROUPING function. More...

Member Typedef Documentation

◆ super

typedef Item_field Item_default_value::super

private

Constructor & Destructor Documentation

◆ Item_default_value()

Item_default_value::Item_default_value	(	const POS &	pos,
		Item *	a = `nullptr`
	)

inline

Member Function Documentation

◆ argument()

Item * Item_default_value::argument ( ) const

inline

◆ bind_fields()

void Item_default_value::bind_fields ( )

overridevirtual

Bind objects from the current execution context to field objects in item trees.

Typically used to bind Field objects from TABLEs to Item_field objects.

Reimplemented from Item_field.

◆ check_column_privileges()

bool Item_default_value::check_column_privileges ( uchar * arg )

inlineoverridevirtual

Check privileges of base table column.

Reimplemented from Item_field.

◆ check_gcol_depend_default_processor()

bool Item_default_value::check_gcol_depend_default_processor ( uchar * args )

inlineoverridevirtual

Check if a generated expression depends on DEFAULT function with specific column name as argument.

Parameters

[in] args Name of column used as DEFAULT function argument.

Returns: false if the function is not DEFAULT(args), otherwise true.

Reimplemented from Item.

◆ cleanup()

void Item_default_value::cleanup ( )

inlineoverridevirtual

Called for every Item after use (preparation and execution).

Release all allocated resources, such as dynamic memory. Prepare for new execution by clearing cached values. Do not remove values allocated during preparation, destructor handles this.

Reimplemented from Item_field.

◆ collect_item_field_or_view_ref_processor()

bool Item_default_value::collect_item_field_or_view_ref_processor ( uchar * )

overridevirtual

Collects fields and view references that have the qualifying table in the specified query block.

Reimplemented from Item_field.

◆ do_itemize()

bool Item_default_value::do_itemize	(	Parse_context *	pc,
		Item **	res
	)

overridevirtual

The core function that does the actual itemization.

itemize() is just a wrapper over this.

Reimplemented from Item_field.

◆ eq()

bool Item_default_value::eq ( const Item * item ) const

overridevirtual

Compare this item with another item for equality.

If both pointers are the same, the items are equal. Both items must be of same type. For literal values, metadata must be the same and the values must be equal. Strings are compared with the embedded collation. For column references, table references and column names must be the same. For functions, the function type, function properties and arguments must be equal. Otherwise, see specific implementations.

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_multi_eq)

Reimplemented from Item_field.

◆ fix_fields()

bool Item_default_value::fix_fields	(	THD *	thd,
		Item **	reference
	)

overridevirtual

Resolve the name of a column reference.

The method resolves the column reference represented by 'this' as a column present in one of: FROM clause, SELECT clause, GROUP BY clause of a query Q, or in outer queries that contain Q.

The name resolution algorithm used is (where [T_j] is an optional table name that qualifies the column name):

resolve_column_reference([T_j].col_ref_i)
{
  search for a column or derived column named col_ref_i
  [in table T_j] in the FROM clause of Q;
 
  if such a column is NOT found AND    // Lookup in outer queries.
     there are outer queries
  {
    for each outer query Q_k beginning from the inner-most one
    {
      search for a column or derived column named col_ref_i
      [in table T_j] in the FROM clause of Q_k;
 
      if such a column is not found
        Search for a column or derived column named col_ref_i
        [in table T_j] in the SELECT and GROUP clauses of Q_k.
    }
  }
}

Notice that compared to Item_ref::fix_fields, here we first search the FROM clause, and then we search the SELECT and GROUP BY clauses.

For the case where a table reference is already set for the field, we just need to make a call to set_field(). This is true for a cloned field used during condition pushdown to derived tables. A cloned field inherits table reference, depended_from, context and field from the original field. set_field() ensures all other members are set correctly.

Parameters

[in]	thd	current thread
[in,out]	reference	view column if this item was resolved to a view column

Returns: false on success, true on error

Reimplemented from Item_field.

◆ get_tmp_table_item()

Item * Item_default_value::get_tmp_table_item ( THD * thd )

inlineoverridevirtual

If an Item is materialized in a temporary table, a different Item may have to be used in the part of the query that runs after the materialization.

For instance, if the Item was an Item_field, the new Item_field needs to point into the temporary table instead of the original one, but if, on the other hand, the Item was a literal constant, it can be reused as-is. This function encapsulates these policies for the different kinds of Items. See also get_tmp_table_field().

TODO: Document how aggregate functions (Item_sum) are handled.

Reimplemented from Item_field.

◆ print()

void Item_default_value::print	(	const THD *	,
		String *	str,
		enum_query_type
	)		const

overridevirtual

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;
to generate a SQL-query that looks like a prepared statement for query_rewrite
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_field.

◆ replace_item_field()

Item * Item_default_value::replace_item_field ( uchar * argp )

overridevirtual

If this default value is the target of replacement, replace it with the info object's item or, if the item is found inside a subquery, the target is an outer reference, so we create a new Item_field, mark it accordingly and replace with that instead.

Parameters

argp	An info object of type Item::Item_field_replacement.

Returns: the resulting item, replaced or not, or nullptr if error

Reimplemented from Item_field.

◆ save_in_field_inner()

type_conversion_status Item_default_value::save_in_field_inner	(	Field *	field,
		bool	no_conversions
	)

overrideprotectedvirtual

Helper function which does all of the work for save_in_field(Field*, bool), except some error checking common to all subclasses, which is performed by save_in_field() itself.

Subclasses that need to specialize the behaviour of save_in_field(), should override this function instead of save_in_field().

Parameters

[in,out]	field	the field to save the item into
	no_conversions	whether or not to allow conversions of the value

Returns: the status from saving into the field

Return values

TYPE_OK	item saved without any errors or warnings
!=	TYPE_OK there were errors or warnings when saving the item

Reimplemented from Item_field.

◆ transform()

Item * Item_default_value::transform	(	Item_transformer	transformer,
		uchar *	arg
	)

overridevirtual

Perform a generic transformation of the Item tree, by adding zero or more additional Item objects to it.

Parameters

	transformer	Transformer function
[in,out]	arg	Pointer to struct used by transformer function

Returns: Returned item tree after transformation, NULL if error

Transformation is performed as follows:

transform()
{
  transform children if any;
  return this->*some_transformer(...);
}

Note that unlike Item::compile(), transform() does not support an analyzer function, ie. all children are unconditionally invoked.

Item::transform() should handle all transformations during preparation. Notice that all transformations are permanent; they are not rolled back.

Use Item::compile() to perform transformations during optimization.

Reimplemented from Item.

◆ type()

enum Type Item_default_value::type ( ) const

inlineoverridevirtual

Reimplemented from Item_field.

◆ used_tables()

table_map Item_default_value::used_tables ( ) const

inlineoverridevirtual

Reimplemented from Item_field.

◆ walk()

bool Item_default_value::walk	(	Item_processor	processor,
		enum_walk	walk,
		uchar *	arg
	)

inlineoverridevirtual

Traverses a tree of Items in prefix and/or postfix order.

Optionally walks into subqueries.

Parameters

processor	processor function to be invoked per item returns true to abort traversal, false to continue
walk	controls how to traverse the item tree enum_walk::PREFIX: call processor before invoking children enum_walk::POSTFIX: call processor after invoking children enum_walk::SUBQUERY go down into subqueries walk values are bit-coded and may be combined. Omitting both enum_walk::PREFIX and enum_walk::POSTFIX is undefined behaviour.
arg	Optional pointer to a walk-specific object

Return values

false	walk succeeded
true	walk aborted by agreement, an error may have been reported

Reimplemented from Item.

Member Data Documentation

◆ arg

Item* Item_default_value::arg

private

The argument for this function.

◆ m_rowbuffer_saved

uchar* Item_default_value::m_rowbuffer_saved {nullptr}

private

Pointer to row buffer that was used to calculate field value offset.

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

sql/item.h
sql/item.cc

Public Member Functions

Protected Member Functions

Private Types

Private Attributes

Additional Inherited Members

Member Typedef Documentation

◆ super

Constructor & Destructor Documentation

◆ Item_default_value()

Member Function Documentation

◆ argument()

◆ bind_fields()

◆ check_column_privileges()

◆ check_gcol_depend_default_processor()

◆ cleanup()

◆ collect_item_field_or_view_ref_processor()

◆ do_itemize()

◆ eq()

◆ fix_fields()

◆ get_tmp_table_item()

◆ print()

◆ replace_item_field()

◆ save_in_field_inner()

◆ transform()

◆ type()

◆ used_tables()

◆ walk()

Member Data Documentation

◆ arg

◆ m_rowbuffer_saved