MySQL  8.0.18
Source Code Documentation
Item_string Class Reference

#include <item.h>

Inheritance diagram for Item_string:
Item_basic_constant Item Parse_tree_node_tmpl< Context > Item_partition_func_safe_string Item_static_string_func PTI_literal_underscore_charset_bin_num PTI_literal_underscore_charset_hex_num PTI_text_literal Item_blob Item_empty_string Item_func_icu_version Item_func_version PTI_text_literal_concat PTI_text_literal_nchar_string PTI_text_literal_text_string PTI_text_literal_underscore_charset

Public Member Functions

 Item_string (const char *str, size_t length, const CHARSET_INFO *cs, Derivation dv=DERIVATION_COERCIBLE, uint repertoire=MY_REPERTOIRE_UNICODE30)
 
 Item_string (const POS &pos, const char *str, size_t length, const CHARSET_INFO *cs, Derivation dv=DERIVATION_COERCIBLE, uint repertoire=MY_REPERTOIRE_UNICODE30)
 
 Item_string (const CHARSET_INFO *cs, Derivation dv=DERIVATION_COERCIBLE)
 
 Item_string (const Name_string name_par, const char *str, size_t length, const CHARSET_INFO *cs, Derivation dv=DERIVATION_COERCIBLE, uint repertoire=MY_REPERTOIRE_UNICODE30)
 
 Item_string (const POS &pos, const Name_string name_par, const char *str, size_t length, const CHARSET_INFO *cs, Derivation dv=DERIVATION_COERCIBLE, uint repertoire=MY_REPERTOIRE_UNICODE30)
 
 Item_string (const POS &pos, const Name_string name_par, const LEX_CSTRING &literal, const CHARSET_INFO *cs, Derivation dv=DERIVATION_COERCIBLE, uint repertoire=MY_REPERTOIRE_UNICODE30)
 
void set_str_with_copy (const char *str_arg, uint length_arg)
 
void set_repertoire_from_value ()
 
enum Type type () const override
 
double val_real () override
 
longlong val_int () override
 
Stringval_str (String *) override
 
my_decimalval_decimal (my_decimal *) override
 
bool get_date (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) override
 
bool get_time (MYSQL_TIME *ltime) override
 
enum Item_result result_type () const override
 
bool eq (const Item *item, bool binary_cmp) const override
 
Itemclone_item () const override
 
Itemsafe_charset_converter (THD *thd, const CHARSET_INFO *tocs) override
 
Itemcharset_converter (THD *thd, const CHARSET_INFO *tocs, bool lossless)
 Convert a string item into the requested character set. More...
 
void append (char *str, size_t length)
 
void print (const THD *thd, String *str, enum_query_type query_type) const override
 
bool check_partition_func_processor (uchar *) override
 Check if a partition function is allowed. More...
 
bool is_cs_specified () const
 Return true if character-set-introducer was explicitly specified in the original query for this item (text literal). More...
 
void set_cs_specified (bool cs_specified)
 Set the value of m_cs_specified attribute. More...
 
void mark_result_as_const ()
 
- Public Member Functions inherited from Item_basic_constant
 Item_basic_constant ()
 
 Item_basic_constant (const POS &pos)
 
void set_used_tables (table_map map)
 
table_map used_tables () const override
 
bool check_function_as_value_generator (uchar *) override
 Check if this item is allowed for a virtual column or inside a default expression. More...
 
void cleanup () override
 
bool basic_const_item () const override
 Returns true if this is a simple constant item like an integer, not a constant expression. More...
 
void set_str_value (String *str)
 
- 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...
 
virtual ~Item () override
 
virtual bool itemize (Parse_context *pc, Item **res)
 The same as contextualize()/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 make_field (Send_field *field)
 
virtual Fieldmake_string_field (TABLE *table)
 Create a field to hold a string value from an item. More...
 
virtual bool fix_fields (THD *, Item **)
 
virtual void fix_after_pullout (SELECT_LEX *parent_select, SELECT_LEX *removed_select)
 Fix after tables have been moved from one select_lex level to the parent level, e.g by semijoin conversion. More...
 
void quick_fix_field ()
 
virtual void set_can_use_prefix_key ()
 
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...
 
virtual void save_org_in_field (Field *field)
 
virtual bool send (Protocol *protocol, String *str)
 This is only called from items that is not of type item_field. More...
 
bool evaluate (THD *thd, String *str)
 Evaluate item, possibly using the supplied buffer. More...
 
virtual enum Item_result numeric_context_result_type () const
 Result type when an item appear in a numeric context. More...
 
enum 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...
 
enum_field_types data_type () const
 Retrieve the derived data type of the Item. More...
 
void set_data_type (enum_field_types data_type)
 Set the data type of the current Item. More...
 
void set_data_type_bool ()
 
void set_data_type_longlong ()
 Set the data type of the Item to be longlong. More...
 
void set_data_type_decimal (uint8 precision, uint8 dec)
 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_init ()
 Initialize an Item to be of VARCHAR type, other properties undetermined. 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 (ulonglong 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 (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_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_geometry ()
 Set the Item to be of GEOMETRY type. More...
 
void set_data_type_from_result (Item_result result, uint32 length)
 Set type information of Item from "result" information. More...
 
void set_data_type_from_item (Item *item)
 Set data type properties of the item from the properties of another item. More...
 
virtual Item_result cast_to_int_type () const
 
void aggregate_type (Bounds_checked_array< Item *> items)
 Aggregates data types from array of items into current item. More...
 
virtual enum_monotonicity_info get_monotonicity_info () const
 
bool is_null_value ()
 For template-compatibility with Field. More...
 
virtual longlong val_int_endpoint (bool left_endp, bool *incl_endp)
 
virtual longlong val_date_temporal ()
 Return date value of item in packed longlong format. More...
 
virtual longlong val_time_temporal ()
 Return time value of item in packed longlong format. 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 val_temporal_with_round (enum_field_types type, uint8 dec)
 Get date or time value in packed longlong format. More...
 
ulonglong val_uint ()
 
virtual Stringval_str_ascii (String *str)
 
virtual bool val_bool ()
 
virtual bool val_json (Json_wrapper *result)
 Get a JSON value from an Item. More...
 
virtual 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)
 Calculate the filter contribution that is relevant for table 'filter_for_table' for this item. More...
 
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...
 
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 Fieldget_tmp_table_field ()
 
virtual Fieldtmp_table_field (TABLE *)
 
virtual const char * full_name () const
 
virtual table_map not_null_tables () 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...
 
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, bool used_alias) const
 Prints the item when it's part of ORDER BY and GROUP BY. More...
 
virtual void update_used_tables ()
 
virtual void split_sum_func (THD *, Ref_item_array, List< Item > &)
 
void split_sum_func2 (THD *thd, Ref_item_array ref_item_array, List< Item > &fields, Item **ref, bool skip_registered)
 
virtual bool get_timeval (struct timeval *tm, int *warnings)
 Get timestamp in "struct timeval" format. More...
 
virtual bool is_null ()
 
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 void set_result_field (Field *)
 
virtual bool is_result_field () const
 
virtual Fieldget_result_field () const
 
virtual bool is_bool_func () const
 
virtual void save_in_result_field (bool no_conversions)
 
virtual void no_rows_in_result ()
 
virtual Itemcopy_or_same (THD *)
 
virtual Itemcopy_andor_structure (THD *)
 
virtual Itemreal_item ()
 
virtual Itemsubstitutional_item ()
 
virtual void set_runtime_created ()
 
virtual Itemget_tmp_table_item (THD *thd)
 
virtual const CHARSET_INFOcompare_collation () const
 
virtual const CHARSET_INFOcharset_for_protocol () const
 
virtual bool walk (Item_processor processor, enum_walk walk, uchar *arg)
 Traverses a tree of Items in prefix and/or postfix order. More...
 
template<class T >
bool walk_helper_thunk (uchar *arg)
 
virtual Itemtransform (Item_transformer transformer, uchar *arg)
 Perform a generic transformation of the Item tree, by adding zero or more additional Item objects to it. More...
 
virtual Itemcompile (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 collect_item_field_processor (uchar *)
 
virtual bool add_field_to_set_processor (uchar *)
 Item::walk function. More...
 
virtual bool visitor_processor (uchar *arg)
 A processor to handle the select lex visitor framework. More...
 
virtual bool add_field_to_cond_set_processor (uchar *)
 Item::walk function. More...
 
virtual bool remove_column_from_bitmap (uchar *arg)
 Visitor interface for removing all column expressions (Item_field) in this expression tree from a bitmap. More...
 
virtual bool find_item_in_field_list_processor (uchar *)
 
virtual bool change_context_processor (uchar *)
 
virtual bool find_item_processor (uchar *arg)
 
virtual bool is_non_const_over_literals (uchar *)
 
virtual bool find_field_processor (uchar *)
 Is this an Item_field which references the given Field argument? More...
 
virtual bool cast_incompatible_args (uchar *)
 Wrap incompatible arguments in CAST nodes to the expected data types. More...
 
virtual bool mark_field_in_map (uchar *arg)
 Mark underlying field in read or write map of a table. More...
 
virtual bool references_select_expr_of (uchar *arg)
 
virtual bool reset_wf_state (uchar *arg)
 Reset execution state for such window function types as determined by arg. More...
 
virtual bool used_tables_for_level (uchar *arg)
 Return used table information for the specified query block (level). More...
 
virtual bool check_column_privileges (uchar *thd)
 Check privileges. 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...
 
bool propagate_derived_used (uchar *)
 Propagate components that use referenced columns from derived tables. More...
 
bool propagate_set_derived_used (uchar *)
 Called by Item::walk() to set all the referenced items' derived_used flag. More...
 
virtual bool aggregate_check_distinct (uchar *)
 
virtual bool aggregate_check_group (uchar *)
 
virtual bool is_strong_side_column_not_in_fd (uchar *)
 
virtual bool is_column_not_in_fd (uchar *)
 
virtual Bool3 local_column (const SELECT_LEX *) const
 
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...
 
virtual bool cache_const_expr_analyzer (uchar **cache_item)
 Check if an item is a constant one and can be cached. More...
 
Itemcache_const_expr_transformer (uchar *item)
 Cache item if needed. More...
 
virtual bool equality_substitution_analyzer (uchar **)
 
virtual Itemequality_substitution_transformer (uchar *)
 
virtual bool subst_argument_checker (uchar **arg)
 
virtual bool explain_subquery_checker (uchar **)
 
virtual Itemexplain_subquery_propagator (uchar *)
 
virtual Itemequal_fields_propagator (uchar *)
 
virtual bool set_no_const_sub (uchar *)
 
virtual Itemreplace_equal_field (uchar *)
 
virtual bool check_valid_arguments_processor (uchar *)
 
virtual bool check_gcol_depend_default_processor (uchar *args)
 Check if a generated expression depends on DEFAULT function with specific column name as argument. More...
 
virtual Itemthis_item ()
 
virtual const Itemthis_item () const
 
virtual Item ** this_item_addr (THD *, Item **addr_arg)
 
virtual uint cols () const
 
virtual Itemelement_index (uint)
 
virtual Item ** addr (uint)
 
virtual bool check_cols (uint c)
 
virtual bool null_inside ()
 
virtual void bring_value ()
 
Fieldtmp_table_field_from_field_type (TABLE *table, bool fixed_length)
 Create a field based on field_type of argument. More...
 
virtual Item_fieldfield_for_view_update ()
 
virtual Itemtruth_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 Itemupdate_value_transformer (uchar *)
 
void delete_self ()
 
virtual bool is_splocal () const
 
virtual Settable_routine_parameterget_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...
 
virtual Field::geometry_type get_geometry_type () const
 
Stringcheck_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, bool binary_cmp, const CHARSET_INFO *cs)
 
virtual bool is_expensive ()
 
uint32 max_char_length () const
 
void fix_char_length (uint32 max_char_length_arg)
 
virtual bool is_outer_field () const
 
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...
 
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_rollup_expr () const
 
void set_rollup_expr ()
 Set the property: this item (tree) contains a reference to a ROLLUP expr. 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...
 
bool is_derived_used () const
 
void mark_subqueries_optimized_away ()
 
virtual bool gc_subst_analyzer (uchar **)
 Analyzer function for GC substitution. More...
 
virtual Itemgc_subst_transformer (uchar *)
 Transformer function for GC substitution. More...
 
virtual bool replace_field_processor (uchar *)
 A processor that replaces any Fields with a Create_field_wrapper. More...
 
bool can_be_substituted_for_gc () const
 Check if this item is of a type that is eligible for GC substitution. More...
 
void aggregate_decimal_properties (Item **item, uint nitems)
 Set precision and decimals of function when this depends on arguments' values for these quantities. More...
 
void aggregate_float_properties (Item **item, 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_char_length (Item **args, uint nitems)
 Set the maximum number of characters required by any of the items in args. More...
 
void aggregate_temporal_properties (Item **item, uint nitems)
 Set fractional seconds precision for temporal functions. More...
 
bool aggregate_string_properties (const char *name, Item **item, uint nitems)
 Aggregate string properties (character set, collation and maximum length) for string function. More...
 
void aggregate_num_type (Item_result result_type, Item **item, uint nitems)
 This function is used to resolve type for numeric result type of CASE, COALESCE, IF and LEAD/LAG. More...
 
virtual bool repoint_const_outer_ref (uchar *arg)
 This function applies only to Item_field objects referred to by an Item_ref object that has been marked as a const_item. More...
 
virtual Fieldget_orig_field ()
 
virtual void set_orig_field (Field *)
 
virtual bool strip_db_table_name_processor (uchar *)
 
virtual bool set_table_name (uchar *)
 Noop in Item for items that are not subclasses of Item_ident. More...
 
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 bool returns_array () const
 Whether the item returns array of its data type. More...
 
virtual void allow_array_cast ()
 
A helper funciton to ensure proper usage of CAST(. More...
 
- Public Member Functions inherited from Parse_tree_node_tmpl< Context >
virtual ~Parse_tree_node_tmpl ()
 
bool is_contextualized () const
 
virtual bool contextualize (Context *pc)
 Do all context-sensitive things and mark the node as contextualized. More...
 
virtual bool contextualize_ (Context *)
 
Intermediate version of the contextualize() function More...
 
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

 Item_string (const POS &pos)
 
void init (const char *str, size_t length, const CHARSET_INFO *cs, Derivation dv, uint repertoire)
 
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
Stringmake_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...
 
Stringval_string_from_real (String *str)
 
Stringval_string_from_int (String *str)
 
Stringval_string_from_decimal (String *str)
 
Stringval_string_from_date (String *str)
 
Stringval_string_from_datetime (String *str)
 
Stringval_string_from_time (String *str)
 
my_decimalval_decimal_from_real (my_decimal *decimal_value)
 
my_decimalval_decimal_from_int (my_decimal *decimal_value)
 
my_decimalval_decimal_from_string (my_decimal *decimal_value)
 
my_decimalval_decimal_from_date (my_decimal *decimal_value)
 
my_decimalval_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 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...
 
Stringerror_str ()
 Get the value to return from val_str() in case of errors. More...
 
Stringnull_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 ()
 

Private Types

typedef Item_basic_constant super
 

Private Attributes

bool m_cs_specified
 

Additional Inherited Members

- Public Types inherited from Item
enum  Type {
  INVALID_ITEM = 0, FIELD_ITEM, 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,
  FIELD_BIT_ITEM, NULL_RESULT_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_CONST_PROPAG = 1, MARKER_BIT = 4, MARKER_FUNC_DEP_NOT_NULL = 5,
  MARKER_DISTINCT_GROUP = 6, 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 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_INFOdefault_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
Itemnext_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 maybe_null
 True if this item may be null. 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...
 
- 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
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_ROLLUP_EXPR = 0x10
 Set if the item or one or more of the underlying items contains a ROLLUP expression. 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

Constructor & Destructor Documentation

◆ Item_string() [1/7]

Item_string::Item_string ( const POS pos)
inlineexplicitprotected

◆ Item_string() [2/7]

Item_string::Item_string ( const char *  str,
size_t  length,
const CHARSET_INFO cs,
Derivation  dv = DERIVATION_COERCIBLE,
uint  repertoire = MY_REPERTOIRE_UNICODE30 
)
inline

◆ Item_string() [3/7]

Item_string::Item_string ( const POS pos,
const char *  str,
size_t  length,
const CHARSET_INFO cs,
Derivation  dv = DERIVATION_COERCIBLE,
uint  repertoire = MY_REPERTOIRE_UNICODE30 
)
inline

◆ Item_string() [4/7]

Item_string::Item_string ( const CHARSET_INFO cs,
Derivation  dv = DERIVATION_COERCIBLE 
)
inline

◆ Item_string() [5/7]

Item_string::Item_string ( const Name_string  name_par,
const char *  str,
size_t  length,
const CHARSET_INFO cs,
Derivation  dv = DERIVATION_COERCIBLE,
uint  repertoire = MY_REPERTOIRE_UNICODE30 
)
inline

◆ Item_string() [6/7]

Item_string::Item_string ( const POS pos,
const Name_string  name_par,
const char *  str,
size_t  length,
const CHARSET_INFO cs,
Derivation  dv = DERIVATION_COERCIBLE,
uint  repertoire = MY_REPERTOIRE_UNICODE30 
)
inline

◆ Item_string() [7/7]

Item_string::Item_string ( const POS pos,
const Name_string  name_par,
const LEX_CSTRING literal,
const CHARSET_INFO cs,
Derivation  dv = DERIVATION_COERCIBLE,
uint  repertoire = MY_REPERTOIRE_UNICODE30 
)
inline

Member Function Documentation

◆ append()

void Item_string::append ( char *  str,
size_t  length 
)
inline

◆ charset_converter()

Item * Item_string::charset_converter ( THD thd,
const CHARSET_INFO tocs,
bool  lossless 
)

Convert a string item into the requested character set.

Parameters
thdThread handle.
tocsCharacter set to to convert the string to.
losslessWhether data loss is acceptable.
Returns
A new item representing the converted string.

◆ check_partition_func_processor()

bool Item_string::check_partition_func_processor ( uchar )
inlineoverridevirtual

Check if a partition function is allowed.

Returns
whether a partition function is not accepted

check_partition_func_processor is used to check if a partition function uses an allowed function. An allowed function will always ensure that X=Y guarantees that also part_function(X)=part_function(Y) where X is a set of partition fields and so is Y. The problems comes mainly from character sets where two equal strings can be quite unequal. E.g. the german character for double s is equal to 2 s.

The default is that an item is not allowed in a partition function. Allowed functions can never depend on server version, they cannot depend on anything related to the environment. They can also only depend on a set of fields in the table itself. They cannot depend on other tables and cannot contain any queries and cannot contain udf's or similar. If a new Item class is defined and it inherits from a class that is allowed in a partition function then it is very important to consider whether this should be inherited to the new class. If not the function below should be defined in the new Item class.

The general behaviour is that most integer functions are allowed. If the partition function contains any multi-byte collations then the function check_part_func_fields will report an error on the partition function independent of what functions are used. So the only character sets allowed are single character collation and even for those only a limited set of functions are allowed. The problem with multi-byte collations is that almost every string function has the ability to change things such that two strings that are equal will not be equal after manipulated by a string function. E.g. two strings one contains a double s, there is a special german character that is equal to two s. Now assume a string function removes one character at this place, then in one the double s will be removed and in the other there will still be one s remaining and the strings are no longer equal and thus the partition function will not sort equal strings into the same partitions.

So the check if a partition function is valid is two steps. First check that the field types are valid, next check that the partition function is valid. The current set of partition functions valid assumes that there are no multi-byte collations amongst the partition fields.

Reimplemented from Item.

Reimplemented in Item_static_string_func.

◆ clone_item()

Item* Item_string::clone_item ( ) const
inlineoverridevirtual
Returns
cloned item if it is constant
Return values
nullptrif this is not const

Reimplemented from Item.

◆ eq()

bool Item_string::eq ( const Item item,
bool  binary_cmp 
) const
overridevirtual

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.

◆ get_date()

bool Item_string::get_date ( MYSQL_TIME ltime,
my_time_flags_t  fuzzydate 
)
inlineoverridevirtual

Implements Item.

◆ get_time()

bool Item_string::get_time ( MYSQL_TIME ltime)
inlineoverridevirtual

Implements Item.

◆ init()

void Item_string::init ( const char *  str,
size_t  length,
const CHARSET_INFO cs,
Derivation  dv,
uint  repertoire 
)
inlineprotected

◆ is_cs_specified()

bool Item_string::is_cs_specified ( ) const
inline

Return true if character-set-introducer was explicitly specified in the original query for this item (text literal).

This operation is to be called from Item_string::print(). The idea is that when a query is generated (re-constructed) from the Item-tree, character-set-introducers should appear only for those literals, where they were explicitly specified by the user. Otherwise, that may lead to loss collation information (character set introducers implies default collation for the literal).

Basically, that makes sense only for views and hopefully will be gone one day when we start using original query as a view definition.

Returns
This operation returns the value of m_cs_specified attribute.
Return values
trueif character set introducer was explicitly specified in the original query.
falseotherwise.

◆ mark_result_as_const()

void Item_string::mark_result_as_const ( )
inline

◆ print()

void Item_string::print ( const THD thd,
String str,
enum_query_type  query_type 
) const
overridevirtual
See also
enum_query_type. For us to be able to print a query (in debugging, optimizer trace, EXPLAIN EXTENDED) without changing the query's result, this function must not modify the item's content. Not even a realloc() of str_value is permitted: Item_func_concat::val_str(), Item_func_repeat::val_str(), Item_func_encode::val_str() depend on the allocated length; a change of this length can influence results of CONCAT(), REPEAT(), ENCODE()...

Reimplemented from Item.

Reimplemented in Item_static_string_func.

◆ result_type()

enum Item_result Item_string::result_type ( ) const
inlineoverridevirtual

Reimplemented from Item.

◆ safe_charset_converter()

Item * Item_string::safe_charset_converter ( THD thd,
const CHARSET_INFO tocs 
)
overridevirtual

Reimplemented from Item.

Reimplemented in Item_static_string_func.

◆ save_in_field_inner()

type_conversion_status Item_string::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]fieldthe field to save the item into
no_conversionswhether or not to allow conversions of the value
Returns
the status from saving into the field
Return values
TYPE_OKitem saved without any errors or warnings
!=TYPE_OK there were errors or warnings when saving the item

Reimplemented from Item.

◆ set_cs_specified()

void Item_string::set_cs_specified ( bool  cs_specified)
inline

Set the value of m_cs_specified attribute.

m_cs_specified attribute shows whether character-set-introducer was explicitly specified in the original query for this text literal or not. The attribute makes sense (is used) only for views.

This operation is to be called from the parser during parsing an input query.

◆ set_repertoire_from_value()

void Item_string::set_repertoire_from_value ( )
inline

◆ set_str_with_copy()

void Item_string::set_str_with_copy ( const char *  str_arg,
uint  length_arg 
)
inline

◆ type()

enum Type Item_string::type ( ) const
inlineoverridevirtual

Implements Item.

Reimplemented in Item_blob.

◆ val_decimal()

my_decimal * Item_string::val_decimal ( my_decimal decimal_value)
overridevirtual

Implements Item.

◆ val_int()

longlong Item_string::val_int ( void  )
overridevirtual

Implements Item.

◆ val_real()

double Item_string::val_real ( void  )
overridevirtual

Implements Item.

◆ val_str()

String* Item_string::val_str ( String )
inlineoverridevirtual

Implements Item.

Member Data Documentation

◆ m_cs_specified

bool Item_string::m_cs_specified
private

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