field.h File Reference

#include <assert.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <algorithm>
#include <optional>
#include "decimal.h"
#include "field_types.h"
#include "lex_string.h"
#include "my_alloc.h"
#include "my_base.h"
#include "my_bitmap.h"
#include "my_dbug.h"
#include "my_double2ulonglong.h"
#include "my_inttypes.h"
#include "my_time.h"
#include "mysql/binlog/event/export/binary_log_funcs.h"
#include "mysql/strings/dtoa.h"
#include "mysql/strings/m_ctype.h"
#include "mysql/udf_registration_types.h"
#include "mysql_com.h"
#include "mysql_time.h"
#include "sql/dd/types/column.h"
#include "sql/field_common_properties.h"
#include "sql/gis/srid.h"
#include "sql/sql_bitmap.h"
#include "sql/sql_const.h"
#include "sql/sql_error.h"
#include "sql/table.h"
#include "sql_string.h"
#include "template_utils.h"

Go to the source code of this file.

Classes
class	Value_generator
	Used for storing information associated with generated column, default values generated from expression or check constraint expression. More...
class	Field
class	Create_field_wrapper
	This class is a substitute for the Field classes during CREATE TABLE. More...
class	Field_num
class	Field_str
class	Field_longstr
class	Field_real
class	Field_decimal
class	Field_new_decimal
class	Field_tiny
class	Field_short
class	Field_medium
class	Field_long
class	Field_longlong
class	Field_float
class	Field_double
class	Field_null
class	Field_temporal
class	Field_temporal_with_date
	Abstract class for types with date with optional time, with or without fractional part: DATE, DATETIME, DATETIME(N), TIMESTAMP, TIMESTAMP(N). More...
class	Field_temporal_with_date_and_time
	Abstract class for types with date and time, with or without fractional part: DATETIME, DATETIME(N), TIMESTAMP, TIMESTAMP(N). More...
class	Field_temporal_with_date_and_timef
	Abstract class for types with date and time, with fractional part: DATETIME, DATETIME(N), TIMESTAMP, TIMESTAMP(N). More...
class	Field_timestamp
class	Field_timestampf
class	Field_year
class	Field_newdate
class	Field_time_common
	Abstract class for TIME and TIME(N). More...
class	Field_time
class	Field_timef
class	Field_datetime
class	Field_datetimef
class	Field_string
class	Field_varstring
class	Field_blob
class	Field_geom
class	Field_json
	A field that stores a JSON value. More...
class	Field_typed_array
	Field that stores array of values of the same type. More...
class	Field_enum
class	Field_set
class	Field_bit
class	Field_bit_as_char
	BIT field represented as chars for non-MyISAM tables. More...
class	Send_field
class	Copy_field

Macros
#define	portable_sizeof_char_ptr   8
#define	IS_EQUAL_NO   0
#define	IS_EQUAL_YES   1
#define	IS_EQUAL_PACK_LENGTH   2
#define	my_charset_numeric   my_charset_latin1
#define	MY_REPERTOIRE_NUMERIC   MY_REPERTOIRE_ASCII
#define	ASSERT_COLUMN_MARKED_FOR_READ
#define	ASSERT_COLUMN_MARKED_FOR_WRITE

Enumerations
enum	enum_check_fields : int { CHECK_FIELD_IGNORE = 0 , CHECK_FIELD_WARN , CHECK_FIELD_ERROR_FOR_NULL }
enum	Derivation {   DERIVATION_IGNORABLE = 6 , DERIVATION_NUMERIC = 5 , DERIVATION_COERCIBLE = 4 , DERIVATION_SYSCONST = 3 ,   DERIVATION_IMPLICIT = 2 , DERIVATION_NONE = 1 , DERIVATION_EXPLICIT = 0 }
	For use. More...
enum	column_format_type { COLUMN_FORMAT_TYPE_DEFAULT = 0 , COLUMN_FORMAT_TYPE_FIXED = 1 , COLUMN_FORMAT_TYPE_DYNAMIC = 2 }
enum	type_conversion_status {   TYPE_OK = 0 , TYPE_NOTE_TIME_TRUNCATED , TYPE_NOTE_TRUNCATED , TYPE_WARN_OUT_OF_RANGE ,   TYPE_WARN_TRUNCATED , TYPE_WARN_INVALID_STRING , TYPE_ERR_NULL_CONSTRAINT_VIOLATION , TYPE_ERR_BAD_VALUE ,   TYPE_ERR_OOM }
	Status when storing a value in a field or converting from one datatype to another. More...
enum	Value_generator_source : short { VGS_GENERATED_COLUMN = 0 , VGS_DEFAULT_EXPRESSION , VGS_CHECK_CONSTRAINT }
	Enum to indicate source for which value generator is used. More...

Functions
bool	fields_are_memcpyable (const Field *to, const Field *from)
	Check if one can copy from “from” to “to” with a simple memcpy(), with pack_length() as the length. More...
type_conversion_status	field_conv_slow (Field *to, const Field *from)
	Copy the value in "from" (assumed to be non-NULL) to "to", doing any required conversions in the process. More...
uint	get_enum_pack_length (int elements)
uint	get_set_pack_length (int elements)
type_conversion_status	decimal_err_to_type_conv_status (int dec_error)
type_conversion_status	time_warning_to_type_conversion_status (const int warn)
	Convert warnings returned from str_to_time() and str_to_datetime() to their corresponding type_conversion_status codes. More...
bool	is_temporal_real_type (enum_field_types type)
	Tests if field real type is temporal, i.e. More...
bool	real_type_with_now_as_default (enum_field_types type)
	Tests if field real type can have "DEFAULT CURRENT_TIMESTAMP", i.e. More...
bool	real_type_with_now_on_update (enum_field_types type)
	Tests if field real type can have "ON UPDATE CURRENT_TIMESTAMP", i.e. More...
enum_field_types	real_type_to_type (enum_field_types real_type)
	Convert temporal real types as returned by field->real_type() to field type as returned by field->type(). More...
enum_field_types	blob_type_from_pack_length (uint pack_length)
	Return the appropriate MYSQL_TYPE_X_BLOB value based on the pack_length. More...
template<bool Is_big_endian>
void	copy_integer (uchar *to, size_t to_length, const uchar *from, size_t from_length, bool is_unsigned)
	Copies an integer value to a format comparable with memcmp(). More...
Field *	make_field (MEM_ROOT *mem_root_arg, TABLE_SHARE *share, uchar *ptr, size_t field_length, uchar *null_pos, uchar null_bit, enum_field_types field_type, const CHARSET_INFO *field_charset, Field::geometry_type geom_type, uchar auto_flags, TYPELIB *interval, const char *field_name, bool is_nullable, bool is_zerofill, bool is_unsigned, uint decimals, bool treat_bit_as_char, uint pack_length_override, std::optional< gis::srid_t > srid, bool is_array)
	This function should only be called from legacy code. More...
Field *	make_field (const Create_field &create_field, TABLE_SHARE *share, const char *field_name, size_t field_length, uchar *ptr, uchar *null_pos, size_t null_bit)
	Instantiates a Field object with the given name and record buffer values. More...
Field *	make_field (const Create_field &create_field, TABLE_SHARE *share, uchar *ptr, uchar *null_pos, size_t null_bit)
	Instantiates a Field object with the given record buffer values. More...
Field *	make_field (const Create_field &create_field, TABLE_SHARE *share)
	Instantiates a Field object without a record buffer. More...
enum_field_types	get_blob_type_from_length (size_t length)
size_t	calc_pack_length (enum_field_types type, size_t length)
size_t	calc_pack_length (dd::enum_column_types type, size_t char_length, size_t elements_count, bool treat_bit_as_char, uint numeric_scale, bool is_unsigned)
	Calculate the length of the in-memory representation of the column from information which can be retrieved from dd::Column or Ha_fk_column_type describing it. More...
uint32	calc_key_length (enum_field_types sql_type, uint32 length, uint32 decimals, bool is_unsigned, uint32 elements)
	Calculate key length for field from its type, length and other attributes. More...
type_conversion_status	set_field_to_null (Field *field)
type_conversion_status	set_field_to_null_with_conversions (Field *field, bool no_conversions)
	Set field to NULL or TIMESTAMP or to next auto_increment number. More...
type_conversion_status	store_internal_with_error_check (Field_new_decimal *field, int conversion_err, my_decimal *value)
Create_field *	generate_create_field (THD *thd, Item *source_item, TABLE *tmp_table)
	Generate a Create_field from an Item. More...
bool	is_blob (enum_field_types sql_type)
const char *	get_field_name_or_expression (THD *thd, const Field *field)
bool	pre_validate_value_generator_expr (Item *expression, const char *name, Value_generator_source source)
	Perform per item-type checks to determine if the expression is allowed for a generated column, default value expression, a functional index or a check constraint. More...

Macro Definition Documentation

ASSERT_COLUMN_MARKED_FOR_READ

#define ASSERT_COLUMN_MARKED_FOR_READ

Value:

  assert(!table ||                    \
         (!table->read_set || bitmap_is_set(table->read_set, field_index())))

ASSERT_COLUMN_MARKED_FOR_WRITE

#define ASSERT_COLUMN_MARKED_FOR_WRITE

Value:

  assert(!table || (!table->write_set || \
                    bitmap_is_set(table->write_set, field_index())))

IS_EQUAL_NO

#define IS_EQUAL_NO   0

IS_EQUAL_PACK_LENGTH

#define IS_EQUAL_PACK_LENGTH   2

IS_EQUAL_YES

#define IS_EQUAL_YES   1

my_charset_numeric

#define my_charset_numeric   my_charset_latin1

MY_REPERTOIRE_NUMERIC

#define MY_REPERTOIRE_NUMERIC   MY_REPERTOIRE_ASCII

portable_sizeof_char_ptr

#define portable_sizeof_char_ptr   8

Enumeration Type Documentation

column_format_type

enum column_format_type

Enumerator
COLUMN_FORMAT_TYPE_DEFAULT
COLUMN_FORMAT_TYPE_FIXED
COLUMN_FORMAT_TYPE_DYNAMIC

Derivation

enum Derivation

For use.

See also

DTCollation::aggregate()

Enumerator
DERIVATION_IGNORABLE
DERIVATION_NUMERIC
DERIVATION_COERCIBLE
DERIVATION_SYSCONST
DERIVATION_IMPLICIT
DERIVATION_NONE
DERIVATION_EXPLICIT

enum_check_fields

enum enum_check_fields : int

Enumerator
CHECK_FIELD_IGNORE
CHECK_FIELD_WARN
CHECK_FIELD_ERROR_FOR_NULL

type_conversion_status

enum type_conversion_status

Status when storing a value in a field or converting from one datatype to another.

The values should be listed in order of increasing seriousness so that if two type_conversion_status variables are compared, the bigger one is most serious.

Enumerator
TYPE_OK	Storage/conversion went fine.
TYPE_NOTE_TIME_TRUNCATED	A minor problem when converting between temporal values, e.g. if datetime is converted to date the time information is lost.
TYPE_NOTE_TRUNCATED	Value was stored, but something was cut. What was cut is considered insignificant enough to only issue a note. Example: trying to store a number with 5 decimal places into a field that can only store 3 decimals. The number rounded to 3 decimal places should be stored. Another example: storing the string "foo " into a VARCHAR(3). The string "foo" is stored in this case, so only whitespace is cut.
TYPE_WARN_OUT_OF_RANGE	Value outside min/max limit of datatype. The min/max value is stored by Field::store() instead (if applicable)
TYPE_WARN_TRUNCATED	Value was stored, but something was cut. What was cut is considered significant enough to issue a warning. Example: storing the string "foo" into a VARCHAR(2). The string "fo" is stored in this case. Another example: storing the string "2010-01-01foo" into a DATE. The garbage in the end of the string is cut in this case.
TYPE_WARN_INVALID_STRING	Value has invalid string data. When present in a predicate with equality operator, range optimizer returns an impossible where.
TYPE_ERR_NULL_CONSTRAINT_VIOLATION	Trying to store NULL in a NOT NULL field.
TYPE_ERR_BAD_VALUE	Store/convert incompatible values, like converting "foo" to a date.
TYPE_ERR_OOM	Out of memory.

Value_generator_source

enum Value_generator_source : short

Enum to indicate source for which value generator is used.

This is needed while unpacking value generator expression and pre-validating the expression for generated column, default expression or check constraint.

Enumerator
VGS_GENERATED_COLUMN
VGS_DEFAULT_EXPRESSION
VGS_CHECK_CONSTRAINT

Function Documentation

blob_type_from_pack_length()

enum_field_types blob_type_from_pack_length ( uint  pack_length )

inline

Return the appropriate MYSQL_TYPE_X_BLOB value based on the pack_length.

Parameters

pack_length

pack_length for BLOB

Return values

MYSQL_TYPE_X_BLOB

corresponding to pack_length.

calc_key_length()

uint32 calc_key_length	(	enum_field_types	sql_type,
		uint32	length,
		uint32	decimals,
		bool	is_unsigned,
		uint32	elements
	)

Calculate key length for field from its type, length and other attributes.

Note

for string fields "length" parameter is assumed to take into account character set.

TODO: Get rid of this function as its code is redundant with Field::key_length() code. However creation of Field object using make_field() just to call Field::key_length() is probably overkill.

calc_pack_length() [1/2]

size_t calc_pack_length	(	dd::enum_column_types	type,
		size_t	char_length,
		size_t	elements_count,
		bool	treat_bit_as_char,
		uint	numeric_scale,
		bool	is_unsigned
	)

Calculate the length of the in-memory representation of the column from information which can be retrieved from dd::Column or Ha_fk_column_type describing it.

This function calculates the amount of memory necessary to store values in the record buffer. It is used in cases when we want to calculate this value from the description of column in the form compatible with dd::Column without constructing full-blown Field object.

Note

The implementation is based on Create_field::init() and Create_field::create_length_to_internal_length().

Parameters

type	Column DD type.
char_length	Column length as stored in DD.
elements_count	Number of elements in column of ENUM/SET type.
treat_bit_as_char	Indicates whether this BIT column is represented as char column internally.
numeric_scale	Column numeric scale as stored in DD.
is_unsigned	Column unsignedness.

calc_pack_length() [2/2]

size_t calc_pack_length	(	enum_field_types	type,
		size_t	length
	)

copy_integer()

template<bool Is_big_endian>

void copy_integer	(	uchar *	to,
		size_t	to_length,
		const uchar *	from,
		size_t	from_length,
		bool	is_unsigned
	)

Copies an integer value to a format comparable with memcmp().

The format is characterized by the following:

• The sign bit goes first and is unset for negative values.
• The representation is big endian.

The function template can be instantiated to copy from little or big endian values.

Template Parameters

Is_big_endian

True if the source integer is big endian.

Parameters

to	Where to write the integer.
to_length	Size in bytes of the destination buffer.
from	Where to read the integer.
from_length	Size in bytes of the source integer
is_unsigned	True if the source integer is an unsigned value.

decimal_err_to_type_conv_status()

type_conversion_status decimal_err_to_type_conv_status ( int  dec_error )

inline

field_conv_slow()

type_conversion_status field_conv_slow	(	Field *	to,
		const Field *	from
	)

Copy the value in "from" (assumed to be non-NULL) to "to", doing any required conversions in the process.

Note that you should only call this if fields_are_memcpyable() is false, since it does an actual conversion on the slow path (and it is not properly tested whether it gives the correct result in all cases if fields_are_memcpyable() is true).

You should never call this with to == from, as they are no-ops.

fields_are_memcpyable()

bool fields_are_memcpyable	(	const Field *	to,
		const Field *	from
	)

Check if one can copy from “from” to “to” with a simple memcpy(), with pack_length() as the length.

This is the case if the types of the two fields are the same and we don't have special copying rules for the type (e.g., blobs, which require allocation, or time functions that require checking for special SQL modes).

You should never call this with to == from, as such copies are no-ops and memcpy() has undefined behavior with overlapping memory areas.

generate_create_field()

Create_field * generate_create_field	(	THD *	thd,
		Item *	source_item,
		TABLE *	tmp_table
	)

Generate a Create_field from an Item.

This function generates a Create_field from an Item by first creating a temporary table Field from the Item, and then creating the Create_field from this Field (there is currently no way to go directly from Item to Create_field). It is used several places:

• In CREATE TABLE AS SELECT for creating the target table definition.
• In functional indexes for creating the hidden generated column from the indexed expression.

Parameters

thd	Thread handler
source_item	The item to generate a Create_field from
tmp_table	A table object which is used to generate a temporary table field, as described above. This doesn't need to be an existing table.

Returns

A Create_field generated from the input item, or nullptr in case of errors.

get_blob_type_from_length()

enum_field_types get_blob_type_from_length

(

size_t

length

)

get_enum_pack_length()

uint get_enum_pack_length ( int  elements )

inline

get_field_name_or_expression()

const char * get_field_name_or_expression	(	THD *	thd,
		const Field *	field
	)

Returns

the expression if the input field is a hidden generated column that represents a functional key part. If not, return the field name. In case of a functional index; the expression is allocated on the THD's MEM_ROOT.

get_set_pack_length()

uint get_set_pack_length ( int  elements )

inline

is_blob()

bool is_blob ( enum_field_types  sql_type )

inline

is_temporal_real_type()

bool is_temporal_real_type ( enum_field_types  type )

inline

Tests if field real type is temporal, i.e.

represents all existing implementations of DATE, TIME, DATETIME or TIMESTAMP types in SQL.

Parameters

type	Field real type, as returned by field->real_type()

Return values

true	If field real type is temporal
false	If field real type is not temporal

make_field() [1/4]

Field * make_field	(	const Create_field &	create_field,
		TABLE_SHARE *	share
	)

Instantiates a Field object without a record buffer.

Parameters

create_field	The column meta data.
share	The table share object.

make_field() [2/4]

Field * make_field	(	const Create_field &	create_field,
		TABLE_SHARE *	share,
		const char *	field_name,
		size_t	field_length,
		uchar *	ptr,
		uchar *	null_pos,
		size_t	null_bit
	)

Instantiates a Field object with the given name and record buffer values.

Parameters

create_field	The column meta data.
share	The table share object.
field_name	Create_field::field_name is overridden with this value when instantiating the Field object.
field_length	Create_field::length is overridden with this value when instantiating the Field object.
ptr	The address of the data bytes.
null_pos	The address of the null bytes.
null_bit	The position of the column's null bit within the row's null bytes.

make_field() [3/4]

Field * make_field	(	const Create_field &	create_field,
		TABLE_SHARE *	share,
		uchar *	ptr,
		uchar *	null_pos,
		size_t	null_bit
	)

Instantiates a Field object with the given record buffer values.

Parameters

create_field	The column meta data.
share	The table share object.
ptr	The start of the record buffer.
null_pos	The address of the null bytes.
null_bit	The position of the column's null bit within the row's null bytes.

make_field() [4/4]

Field * make_field	(	MEM_ROOT *	mem_root_arg,
		TABLE_SHARE *	share,
		uchar *	ptr,
		size_t	field_length,
		uchar *	null_pos,
		uchar	null_bit,
		enum_field_types	field_type,
		const CHARSET_INFO *	field_charset,
		Field::geometry_type	geom_type,
		uchar	auto_flags,
		TYPELIB *	interval,
		const char *	field_name,
		bool	is_nullable,
		bool	is_zerofill,
		bool	is_unsigned,
		uint	decimals,
		bool	treat_bit_as_char,
		uint	pack_length_override,
		std::optional< gis::srid_t >	srid,
		bool	is_array
	)

This function should only be called from legacy code.

pre_validate_value_generator_expr()

bool pre_validate_value_generator_expr	(	Item *	expression,
		const char *	name,
		Value_generator_source	source
	)

Perform per item-type checks to determine if the expression is allowed for a generated column, default value expression, a functional index or a check constraint.

Note that validation of the specific function is done later in procedures open_table_from_share and fix_value_generator_fields.

Parameters

expression	the expression to check for validity
name	used for error reporting
source	Source of value generator(a generated column, a regular column with generated default value or a check constraint).

Returns

false if ok, true otherwise

real_type_to_type()

enum_field_types real_type_to_type ( enum_field_types  real_type )

inline

Convert temporal real types as returned by field->real_type() to field type as returned by field->type().

Parameters

real_type

Real type.

Return values

Field

type.

real_type_with_now_as_default()

bool real_type_with_now_as_default ( enum_field_types  type )

inline

Tests if field real type can have "DEFAULT CURRENT_TIMESTAMP", i.e.

represents TIMESTAMP types in SQL.

Parameters

type	Field type, as returned by field->real_type().

Return values

true	If field real type can have "DEFAULT CURRENT_TIMESTAMP".
false	If field real type can not have "DEFAULT CURRENT_TIMESTAMP".

real_type_with_now_on_update()

bool real_type_with_now_on_update ( enum_field_types  type )

inline

Tests if field real type can have "ON UPDATE CURRENT_TIMESTAMP", i.e.

represents TIMESTAMP types in SQL.

Parameters

type	Field type, as returned by field->real_type().

Return values

true	If field real type can have "ON UPDATE CURRENT_TIMESTAMP".
false	If field real type can not have "ON UPDATE CURRENT_TIMESTAMP".

set_field_to_null()

type_conversion_status set_field_to_null

(

Field *

field

)

The following piece of code is run for the case when a BLOB column that has value NULL is queried with GROUP BY NULL and the result is inserted into a some table's column declared having primitive type (e.g. INT) and NOT NULL.

For example, the following test case will hit this piece of code: CREATE TABLE t1 (a BLOB); CREATE TABLE t2 (a INT NOT NULL);

INSERT t1 VALUES (NULL); INSERT INTO t2(a) SELECT a FROM t1 GROUP BY NULL; <<== Hit here

In general, when set_field_to_null() is called a Field has to be either declared as NULL-able or be marked as temporary NULL-able. But in case of INSERT SELECT from a BLOB field and when GROUP BY NULL is specified the Field object for a destination column doesn't set neither NULL-able nor temporary NULL-able (see setup_copy_fields()).

set_field_to_null_with_conversions()

type_conversion_status set_field_to_null_with_conversions	(	Field *	field,
		bool	no_conversions
	)

Set field to NULL or TIMESTAMP or to next auto_increment number.

Parameters

field	Field to update
no_conversions	Set to 1 if we should return 1 if field can't take null values. If set to 0 we will do store the 'default value' if the field is a special field. If not we will give an error.

Return values

0	Field could take 0 or an automatic conversion was used
-1	Field could not take NULL and no conversion was used. If no_conversion was not set, an error message is printed

store_internal_with_error_check()

type_conversion_status store_internal_with_error_check	(	Field_new_decimal *	field,
		int	conversion_err,
		my_decimal *	value
	)

time_warning_to_type_conversion_status()

type_conversion_status time_warning_to_type_conversion_status ( const int  warn )

inline

Convert warnings returned from str_to_time() and str_to_datetime() to their corresponding type_conversion_status codes.