class Item_field :public Item_ident { protected: void set_field(Field *field); public: Field *field,*result_field; Item_equal *item_equal; bool no_const_subst; /* if any_privileges set to TRUE then here real effective privileges will be stored */ uint have_privileges; /* field need any privileges (for VIEW creation) */ bool any_privileges; Item_field(Name_resolution_context *context_arg, const char *db_arg,const char *table_name_arg, const char *field_name_arg); /* Constructor needed to process subselect with temporary tables (see Item) */ Item_field(THD *thd, Item_field *item); /* Constructor used inside setup_wild(), ensures that field, table, and database names will live as long as Item_field (this is important in prepared statements). */ Item_field(THD *thd, Name_resolution_context *context_arg, Field *field); /* If this constructor is used, fix_fields() won't work, because db_name, table_name and column_name are unknown. It's necessary to call reset_field() before fix_fields() for all fields created this way. */ Item_field(Field *field); enum Type type() const { return FIELD_ITEM; } bool eq(const Item *item, bool binary_cmp) const; double val_real(); longlong val_int(); my_decimal *val_decimal(my_decimal *); String *val_str(String*); double val_result(); longlong val_int_result(); String *str_result(String* tmp); my_decimal *val_decimal_result(my_decimal *); bool val_bool_result(); bool is_null_result(); bool send(Protocol *protocol, String *str_arg); void reset_field(Field *f); bool fix_fields(THD *, Item **); void make_field(Send_field *tmp_field); int save_in_field(Field *field,bool no_conversions); void save_org_in_field(Field *field); table_map used_tables() const; enum Item_result result_type () const { return field->result_type(); } Item_result cast_to_int_type() const { return field->cast_to_int_type(); } enum_field_types field_type() const { return field->type(); } enum_monotonicity_info get_monotonicity_info() const { return MONOTONIC_STRICT_INCREASING; } longlong val_int_endpoint(bool left_endp, bool *incl_endp); Field *get_tmp_table_field() { return result_field; } Field *tmp_table_field(TABLE *t_arg) { return result_field; } bool get_date(MYSQL_TIME *ltime,uint fuzzydate); bool get_date_result(MYSQL_TIME *ltime,uint fuzzydate); bool get_time(MYSQL_TIME *ltime); bool is_null() { return field->is_null(); } void update_null_value(); Item *get_tmp_table_item(THD *thd); bool collect_item_field_processor(uchar * arg); bool find_item_in_field_list_processor(uchar *arg); bool register_field_in_read_map(uchar *arg); bool check_partition_func_processor(uchar *int_arg) {return FALSE;} void cleanup(); bool result_as_longlong() { return field->can_be_compared_as_longlong(); } Item_equal *find_item_equal(COND_EQUAL *cond_equal); bool subst_argument_checker(uchar **arg); Item *equal_fields_propagator(uchar *arg); bool set_no_const_sub(uchar *arg); Item *replace_equal_field(uchar *arg); inline uint32 max_disp_length() { return field->max_display_length(); } Item_field *filed_for_view_update() { return this; } Item *safe_charset_converter(CHARSET_INFO *tocs); int fix_outer_field(THD *thd, Field **field, Item **reference); virtual Item *update_value_transformer(uchar *select_arg); virtual void print(String *str, enum_query_type query_type); bool is_outer_field() const { DBUG_ASSERT(fixed); return field->table->pos_in_table_list->outer_join; } Field::geometry_type get_geometry_type() const { DBUG_ASSERT(field_type() == MYSQL_TYPE_GEOMETRY); return field->get_geometry_type(); } CHARSET_INFO *charset_for_protocol(void) const { return field->charset_for_protocol(); } friend class Item_default_value; friend class Item_insert_value; friend class st_select_lex_unit; };
bool Item_field::eq(const Item *item, bool binary_cmp) const { Item *real_item= ((Item *) item)->real_item(); if (real_item->type() != FIELD_ITEM) return 0; Item_field *item_field= (Item_field*) real_item; if (item_field->field && field) return item_field->field == field; /* We may come here when we are trying to find a function in a GROUP BY clause from the select list. In this case the '100 % correct' way to do this would be to first run fix_fields() on the GROUP BY item and then retry this function, but I think it's better to relax the checking a bit as we will in most cases do the correct thing by just checking the field name. (In cases where we would choose wrong we would have to generate a ER_NON_UNIQ_ERROR). */ return (!my_strcasecmp(system_charset_info, item_field->name, field_name) && (!item_field->table_name || !table_name || (!my_strcasecmp(table_alias_charset, item_field->table_name, table_name) && (!item_field->db_name || !db_name || (item_field->db_name && !strcmp(item_field->db_name, db_name)))))); }