MySQL 8.4.0
Source Code Documentation
Field_null Class Referencefinal

#include <field.h>

Inheritance diagram for Field_null:

Public Member Functions

 Field_null (uchar *ptr_arg, uint32 len_arg, uchar auto_flags_arg, const char *field_name_arg, const CHARSET_INFO *cs)
enum_field_types type () const final
type_conversion_status store (const char *, size_t, const CHARSET_INFO *) final
type_conversion_status store (double) final
 Store double value in Field_string or Field_varstring. More...
type_conversion_status store (longlong, bool) final
type_conversion_status store_decimal (const my_decimal *) final
 Decimal representation of Field_str. More...
type_conversion_status reset () final
double val_real () const final
longlong val_int () const final
my_decimalval_decimal (my_decimal *) const final
Stringval_str (String *, String *value2) const final
int cmp (const uchar *, const uchar *) const final
size_t make_sort_key (uchar *, size_t len) const final
 Writes a copy of the current value in the record buffer, suitable for sorting using byte-by-byte comparison. More...
uint32 pack_length () const final
void sql_type (String &str) const final
uint32 max_display_length () const final
Field_nullclone (MEM_ROOT *mem_root) const final
 Makes a shallow copy of the Field object. More...
- Public Member Functions inherited from Field_str
 Field_str (uchar *ptr_arg, uint32 len_arg, uchar *null_ptr_arg, uchar null_bit_arg, uchar auto_flags_arg, const char *field_name_arg, const CHARSET_INFO *charset)
Item_result result_type () const override
Item_result numeric_context_result_type () const final
 Returns Item_result type of a field when it appears in numeric context such as: SELECT time_column + 1; SELECT SUM(time_column); Examples: More...
uint decimals () const override
void make_send_field (Send_field *field) const override
 Populates a Send_field object with metadata about the column represented by this Field object. More...
uint repertoire () const final
const CHARSET_INFOcharset () const override
void set_charset (const CHARSET_INFO *charset_arg)
void set_field_length (uint32 length) final
enum Derivation derivation () const final
void set_derivation (enum Derivation derivation_arg) final
bool binary () const override
bool str_needs_quotes () const final
uint is_equal (const Create_field *new_field) const override
 Whether a field being created is type-compatible with an existing one. More...
void add_to_cost (CostOfItem *cost) const override
 Update '*cost' with the fact that this Field is accessed. More...
- Public Member Functions inherited from Field
 Field (const Field &)=default
void operator= (Field &)=delete
bool has_insert_default_general_value_expression () const
 Checks if the field is marked as having a general expression to generate default values. More...
bool has_insert_default_datetime_value_expression () const
 Checks if the field is marked as having a datetime value expression to generate default values on inserts. More...
bool has_update_default_datetime_value_expression () const
 Checks if the field is marked as having a datetime value expression to generate default values on updates. More...
bool has_insert_default_constant_expression () const
 Checks if the field is marked as having a constant expression to generate default values. More...
ucharget_null_ptr ()
bool is_flag_set (unsigned flag) const
void set_flag (unsigned flag)
void clear_flag (unsigned flag)
uint32 all_flags () const
virtual bool is_unsigned () const
 Whether the field is signed or not. More...
bool is_gcol () const
bool is_virtual_gcol () const
void set_hidden (dd::Column::enum_hidden_type hidden)
 Sets the hidden type for this field. More...
dd::Column::enum_hidden_type hidden () const
bool is_hidden () const
bool is_hidden_by_system () const
bool is_hidden_by_user () const
bool is_field_for_functional_index () const
 Field (uchar *ptr_arg, uint32 length_arg, uchar *null_ptr_arg, uchar null_bit_arg, uchar auto_flags_arg, const char *field_name_arg)
 This is used as a table name when the table structure is not set up. More...
virtual ~Field ()=default
void reset_warnings ()
void set_tmp_nullable ()
 Turn on temporary nullability for the field. More...
void reset_tmp_nullable ()
 Turn off temporary nullability for the field. More...
void reset_tmp_null ()
 Reset temporary NULL value for field. More...
void set_tmp_null ()
 Set field to temporary value NULL. More...
bool is_tmp_nullable () const
bool is_tmp_null () const
virtual type_conversion_status store_packed (longlong nr)
 Store a temporal value in packed longlong format into a field. More...
virtual type_conversion_status store_time (MYSQL_TIME *ltime, uint8 dec_arg)
 Store MYSQL_TIME value with the given amount of decimal digits into a field. More...
type_conversion_status store_time (MYSQL_TIME *ltime)
 Store MYSQL_TYPE value into a field when the number of fractional digits is not important or is not know. More...
type_conversion_status store (const char *to, size_t length, const CHARSET_INFO *cs, enum_check_fields check_level)
virtual longlong val_time_temporal () const
 Returns TIME value in packed longlong format. More...
virtual longlong val_date_temporal () const
 Returns DATE/DATETIME value in packed longlong format. More...
virtual longlong val_time_temporal_at_utc () const
virtual longlong val_date_temporal_at_utc () const
longlong val_temporal_by_field_type () const
 Returns "native" packed longlong representation of a TIME or DATE/DATETIME field depending on field type. More...
Stringval_str (String *str) const
Stringval_int_as_str (String *val_buffer, bool unsigned_flag) const
 Interpret field value as an integer but return the result as a string. More...
virtual Item_result cmp_type () const
virtual Item_result cast_to_int_type () const
bool gcol_expr_is_equal (const Create_field *field) const
 Check whether generated columns' expressions are the same. More...
virtual bool eq (const Field *field) const
virtual bool eq_def (const Field *field) const
virtual uint32 pack_length_in_rec () const
virtual bool compatible_field_size (uint metadata, Relay_log_info *, uint16, int *order) const
 Check to see if field size is compatible with destination. More...
virtual uint pack_length_from_metadata (uint field_metadata) const
virtual uint row_pack_length () const
int save_field_metadata (uchar *first_byte)
virtual uint32 data_length (ptrdiff_t row_offset=0) const
virtual uint32 max_data_length () const
 Get the maximum size of the data in packed format. More...
virtual bool get_timestamp (my_timeval *tm, int *warnings) const
 Returns a UTC component in struct timeval format. More...
virtual void store_timestamp (const my_timeval *)
 Stores a timestamp value in timeval format in a field. More...
virtual void set_default ()
void evaluate_insert_default_function ()
 Evaluates the INSERT default function and stores the result in the field. More...
void evaluate_update_default_function ()
 Evaluates the UPDATE default function, if one exists, and stores the result in the record buffer. More...
virtual bool zero_pack () const
virtual enum ha_base_keytype key_type () const
virtual uint32 key_length () const
virtual enum_field_types real_type () const
virtual enum_field_types binlog_type () const
int cmp (const uchar *str) const
virtual int cmp_max (const uchar *a, const uchar *b, uint max_len) const
virtual int cmp_binary (const uchar *a, const uchar *b, uint32 max_length=~0L) const
virtual int cmp_offset (ptrdiff_t row_offset) const
virtual int cmp_binary_offset (ptrdiff_t row_offset) const
virtual int key_cmp (const uchar *a, const uchar *b) const
virtual int key_cmp (const uchar *str, uint length) const
virtual bool is_text_key_type () const
bool is_null (ptrdiff_t row_offset=0) const
 Check whether the full table's row is NULL or the Field has value NULL. More...
bool is_real_null (ptrdiff_t row_offset=0) const
 Check whether the Field has value NULL (temporary or actual). More...
bool is_null_in_record (const uchar *record) const
 Check if the Field has value NULL or the record specified by argument has value NULL for this Field. More...
void set_null (ptrdiff_t row_offset=0)
 Set field to value NULL. More...
void set_notnull (ptrdiff_t row_offset=0)
 Set field to value NOT NULL. More...
type_conversion_status check_constraints (int mysql_errno)
 Check NOT NULL constraint on the field after temporary nullability is disabled. More...
void set_check_for_truncated_fields (enum_check_fields check_for_truncated_fields)
 Remember the value of THD::check_for_truncated_fields to handle possible NOT-NULL constraint errors after BEFORE-trigger execution is finished. More...
bool is_nullable () const
uint null_offset (const uchar *record) const
uint null_offset () const
void set_null_ptr (uchar *p_null_ptr, uint p_null_bit)
virtual size_t make_sort_key (uchar *buff, size_t length, size_t trunc_pos) const
 Writes a copy of the current value in the record buffer, suitable for sorting using byte-by-byte comparison. More...
virtual bool optimize_range (uint idx, uint part) const
 Whether this field can be used for index range scans when in the given keypart of the given index. More...
virtual bool can_be_compared_as_longlong () const
virtual void mem_free ()
virtual Fieldnew_field (MEM_ROOT *root, TABLE *new_table) const
Fieldnew_field (MEM_ROOT *root, TABLE *new_table, uchar *new_ptr, uchar *new_null_ptr, uint new_null_bit) const
virtual Fieldnew_key_field (MEM_ROOT *root, TABLE *new_table, uchar *new_ptr, uchar *new_null_ptr, uint new_null_bit) const
Fieldnew_key_field (MEM_ROOT *root, TABLE *new_table, uchar *new_ptr) const
void move_field (uchar *ptr_arg, uchar *null_ptr_arg, uchar null_bit_arg)
virtual void move_field_offset (ptrdiff_t ptr_diff)
virtual void get_image (uchar *buff, size_t length, const CHARSET_INFO *) const
virtual void set_image (const uchar *buff, size_t length, const CHARSET_INFO *)
virtual size_t get_key_image (uchar *buff, size_t length, imagetype type) const
virtual void set_key_image (const uchar *buff, size_t length)
longlong val_int_offset (ptrdiff_t row_offset)
longlong val_int (uchar *new_ptr)
Stringval_str (String *str, uchar *new_ptr)
virtual bool send_to_protocol (Protocol *protocol) const
 Send the value of this field over the protocol using the correct Protocol::store*() function which matches the type of the field. More...
virtual ucharpack (uchar *to, const uchar *from, size_t max_length) const
 Pack the field into a format suitable for storage and transfer. More...
ucharpack (uchar *to) const
virtual const ucharunpack (uchar *to, const uchar *from, uint param_data)
 Unpack a field from row data. More...
const ucharunpack (const uchar *from)
virtual ucharpack_with_metadata_bytes (uchar *to, const uchar *from, uint max_length) const
 This function does the same thing as pack(), except for the difference that max_length does not mean the number of bytes in the output, but the maximum field length from the input (which must be exactly field->max_field_length()). More...
virtual bool pack_diff (uchar **to, ulonglong value_options) const
 Write the field for the binary log in diff format. More...
virtual uint max_packed_col_length () const
 This is a wrapper around pack_length() used by filesort() to determine how many bytes we need for packing "addon fields". More...
uint offset (uchar *record) const
void copy_data (ptrdiff_t src_record_offset)
virtual bool get_date (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) const
virtual bool get_time (MYSQL_TIME *ltime) const
const CHARSET_INFOcharset_for_protocol () const
virtual const CHARSET_INFOsort_charset () const
virtual bool has_charset () const
virtual bool match_collation_to_optimize_range () const
bool set_warning (Sql_condition::enum_severity_level level, unsigned int code, int cut_increment)
 Produce warning or note about data saved into field. More...
bool set_warning (Sql_condition::enum_severity_level level, uint code, int cut_increment, const char *view_db, const char *view_name)
 Produce warning or note about data saved into field. More...
bool warn_if_overflow (int op_result)
 Process decimal library return codes and issue warnings for overflow and truncation. More...
virtual void init (TABLE *table_arg)
longlong convert_decimal2longlong (const my_decimal *val, bool unsigned_flag, bool *has_overflow)
 Conversion from decimal to longlong. More...
virtual uint32 char_length () const
virtual geometry_type get_geometry_type () const
void dbug_print () const
ha_storage_media field_storage_type () const
void set_storage_type (ha_storage_media storage_type_arg)
column_format_type column_format () const
void set_column_format (column_format_type column_format_arg)
virtual type_conversion_status validate_stored_val (THD *thd)
virtual void hash (ulong *nr, ulong *nr2) const
virtual ulonglong get_max_int_value () const
 Get the upper limit of the MySQL integral and floating-point type. More...
virtual const uchardata_ptr () const
 Return a const pointer to the actual data in the record buffer. More...
const ucharfield_ptr () const
 Return a const pointer to where the field is stored in the record buffer. More...
ucharfield_ptr ()
 Return a pointer to where the field is stored in the record buffer. More...
void set_field_ptr (uchar *ptr_arg)
virtual bool is_updatable () const
 Checks whether a string field is part of write_set. More...
bool is_part_of_actual_key (THD *thd, uint cur_index, KEY *cur_index_info) const
 Check whether field is part of the index taking the index extensions flag into account. More...
Key_map get_covering_prefix_keys () const
 Get covering prefix keys. More...
virtual bool is_array () const
 Whether the field is a typed array. More...
virtual uint32 get_length_bytes () const
 Return number of bytes the field's length takes. More...
bool handle_old_value () const
 Whether field's old valued have to be handled. More...
virtual void set_field_index (uint16 field_index)
 Sets field index. More...
uint16 field_index () const
 Returns field index. More...

Additional Inherited Members

- Public Types inherited from Field
enum  enum_auto_flags {
 Flags for Field::auto_flags / Create_field::auto_flags bitmaps. More...
enum  geometry_type {
enum  imagetype { itRAW , itMBR }
- Static Public Member Functions inherited from Field
static bool type_can_have_key_part (enum_field_types)
 Check whether a field type can be partially indexed by a key. More...
static enum_field_types field_type_merge (enum_field_types, enum_field_types)
 Return type of which can carry value of both given types in UNION result. More...
static Item_result result_merge_type (enum_field_types)
 Detect Item_result by given field type of UNION merge result. More...
- Public Attributes inherited from Field_str
uint32 char_length_cache
- Public Attributes inherited from Field
 Pointer to TABLE object that owns this field. More...
const char * orig_db_name {nullptr}
 Pointer to original database name, only non-NULL for a temporary table. More...
const char * orig_table_name {nullptr}
 Pointer to original table name, only non-NULL for a temporary table. More...
const char ** table_name
const char * field_name
Key_map key_start
Key_map part_of_key
 Keys that includes this field except of prefix keys. More...
Key_map part_of_prefixkey
 Prefix keys. More...
Key_map part_of_sortkey
Key_map part_of_key_not_extended
 All keys that include this field, but not extended by the storage engine to include primary key columns. More...
uint32 field_length
uchar null_bit
uchar auto_flags
 Bitmap of flags indicating if field value is auto-generated by default and/or on update, and in which way. More...
bool is_created_from_null_item
 If true, this field was created in create_tmp_field_from_item from a NULL value. More...
bool m_indexed
 True if this field belongs to some index (unlike part_of_key, the index might have only a prefix). More...
LEX_CSTRING m_engine_attribute = EMPTY_CSTR
LEX_CSTRING m_secondary_engine_attribute = EMPTY_CSTR
Value_generatorgcol_info {nullptr}
bool stored_in_db
 Indication that the field is physically stored in tables rather than just generated on SQL queries. More...
Value_generatorm_default_val_expr {nullptr}
 Holds the expression to be used to generate default values. More...
- Static Public Attributes inherited from Field
static constexpr size_t MAX_VARCHAR_WIDTH {65535}
static constexpr size_t MAX_TINY_BLOB_WIDTH {255}
static constexpr size_t MAX_SHORT_BLOB_WIDTH {65535}
static constexpr size_t MAX_MEDIUM_BLOB_WIDTH {16777215}
static constexpr size_t MAX_LONG_BLOB_WIDTH {4294967295}
- Protected Member Functions inherited from Field
ucharpack_int16 (uchar *to, const uchar *from, size_t max_length) const
const ucharunpack_int16 (uchar *to, const uchar *from) const
ucharpack_int24 (uchar *to, const uchar *from, size_t max_length) const
const ucharunpack_int24 (uchar *to, const uchar *from) const
ucharpack_int32 (uchar *to, const uchar *from, size_t max_length) const
const ucharunpack_int32 (uchar *to, const uchar *from) const
ucharpack_int64 (uchar *to, const uchar *from, size_t max_length) const
const ucharunpack_int64 (uchar *to, const uchar *from) const
- Protected Attributes inherited from Field_str
const CHARSET_INFOfield_charset
enum Derivation field_derivation
- Protected Attributes inherited from Field
 Holds the position to the field in record. More...
- Static Protected Attributes inherited from Field
static uchar dummy_null_buffer = ' '

Constructor & Destructor Documentation

◆ Field_null()

Field_null::Field_null ( uchar ptr_arg,
uint32  len_arg,
uchar  auto_flags_arg,
const char *  field_name_arg,
const CHARSET_INFO cs 

Member Function Documentation

◆ clone()

Field_null * Field_null::clone ( MEM_ROOT mem_root) const

Makes a shallow copy of the Field object.

This member function must be overridden in all concrete subclasses. Several of the Field subclasses are concrete even though they are not leaf classes, so the compiler will not always catch this.
mem_rootMEM_ROOT to use for memory allocation.
Return values
NULLIf memory allocation failed.

Implements Field.

◆ cmp()

int Field_null::cmp ( const uchar ,
const uchar  
) const

Implements Field.

◆ make_sort_key()

size_t Field_null::make_sort_key ( uchar buff,
size_t  length 
) const

Writes a copy of the current value in the record buffer, suitable for sorting using byte-by-byte comparison.

Integers are always in big-endian regardless of hardware architecture. At most length bytes are written into the buffer.

buffThe buffer, assumed to be at least length bytes.
lengthNumber of bytes to write.
Return values
Thenumber of bytes actually written.
This is now only used by replication; filesort makes its own sort keys based off of Items, not Fields.

Implements Field.

◆ max_display_length()

uint32 Field_null::max_display_length ( ) const

Reimplemented from Field_str.

◆ pack_length()

uint32 Field_null::pack_length ( ) const

Reimplemented from Field.

◆ reset()

type_conversion_status Field_null::reset ( )

Reimplemented from Field.

◆ sql_type()

void Field_null::sql_type ( String str) const

Implements Field.

◆ store() [1/3]

type_conversion_status Field_null::store ( const char *  ,
size_t  ,

Implements Field_str.

◆ store() [2/3]

type_conversion_status Field_null::store ( double  nr)

Store double value in Field_string or Field_varstring.

Pretty prints double number into field_length characters buffer.


Reimplemented from Field_str.

◆ store() [3/3]

type_conversion_status Field_null::store ( longlong  ,

Implements Field_str.

◆ store_decimal()

type_conversion_status Field_null::store_decimal ( const my_decimal d)

Decimal representation of Field_str.

dvalue for storing
Field_str is the base class for fields implementing [VAR]CHAR, VAR[BINARY], BLOB/TEXT, GEOMETRY, JSON. String value should be converted to floating point value according our rules, so we use double to store value of decimal in string.
Return values

Reimplemented from Field_str.

◆ type()

enum_field_types Field_null::type ( ) const

Implements Field.

◆ val_decimal()

my_decimal * Field_null::val_decimal ( my_decimal ) const

Implements Field.

◆ val_int()

longlong Field_null::val_int ( void  ) const

Implements Field.

◆ val_real()

double Field_null::val_real ( void  ) const

Implements Field.

◆ val_str()

String * Field_null::val_str ( String ,
String value2 
) const

Implements Field.

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