Value_generator Class Reference

Used for storing information associated with generated column, default values generated from expression or check constraint expression. More...

#include <field.h>

Public Member Functions
enum_field_types	get_real_type () const
void	set_field_type (enum_field_types fld_type)
void	backup_stmt_unsafe_flags (uint32 backup_binlog_stmt_flags)
	Set the binary log flags in m_backup_binlog_stmt_flags. More...
uint32	get_stmt_unsafe_flags ()
	Get the binary log flags from m_backup_binlog_stmt_flags. More...
bool	get_field_stored () const
void	set_field_stored (bool stored)
bool	register_base_columns (TABLE *table)
	Calculate the base_columns_map and num_non_virtual_base_cols members of this generated column. More...
uint	non_virtual_base_columns () const
	Get the number of non virtual base columns that this generated column needs. More...
void	dup_expr_str (MEM_ROOT *root, const char *src, size_t len)
	Duplicates a string into expr_str. More...
void	print_expr (THD *thd, String *out)
	Writes the generation expression into a String with proper syntax. More...

Public Attributes
Item *	expr_item {nullptr}
	Item representing the generation expression. More...
LEX_STRING	expr_str {nullptr, 0}
	Text of the expression. More...
uint32	m_backup_binlog_stmt_flags {0}
	Bit field indicating the type of statement for binary logging. More...
Item *	item_list {nullptr}
	List of all items created when parsing and resolving generated expression. More...
MY_BITMAP	base_columns_map
	Bitmap records base columns which a generated column depends on. More...

Private Attributes
enum_field_types	field_type {MYSQL_TYPE_INVALID}
	Real field type. More...
bool	stored_in_db {false}
	Indicates if the field is physically stored in the database. More...
uint	num_non_virtual_base_cols {0}
	How many non-virtual base columns in base_columns_map. More...

Detailed Description

Used for storing information associated with generated column, default values generated from expression or check constraint expression.

Member Function Documentation

backup_stmt_unsafe_flags()

void Value_generator::backup_stmt_unsafe_flags ( uint32  backup_binlog_stmt_flags )

inline

Set the binary log flags in m_backup_binlog_stmt_flags.

Parameters

backup_binlog_stmt_flags

the flags to be backed up

dup_expr_str()

void Value_generator::dup_expr_str	(	MEM_ROOT *	root,
		const char *	src,
		size_t	len
	)

Duplicates a string into expr_str.

Parameters

root	MEM_ROOT to use for allocation
src	source string
len	length of 'src' in bytes

get_field_stored()

bool Value_generator::get_field_stored ( ) const

inline

get_real_type()

enum_field_types Value_generator::get_real_type ( ) const

inline

get_stmt_unsafe_flags()

uint32 Value_generator::get_stmt_unsafe_flags ( )

inline

Get the binary log flags from m_backup_binlog_stmt_flags.

Returns

the flags backed up by unpack_value_generator

non_virtual_base_columns()

uint Value_generator::non_virtual_base_columns ( ) const

inline

Get the number of non virtual base columns that this generated column needs.

Returns

number of non virtual base columns

print_expr()

void Value_generator::print_expr	(	THD *	thd,
		String *	out
	)

Writes the generation expression into a String with proper syntax.

Parameters

thd	THD
out	output String

register_base_columns()

bool Value_generator::register_base_columns

(

TABLE *

table

)

Calculate the base_columns_map and num_non_virtual_base_cols members of this generated column.

Parameters

table

Table with the checked field

Return values

true

if error

set_field_stored()

void Value_generator::set_field_stored ( bool  stored )

inline

set_field_type()

void Value_generator::set_field_type ( enum_field_types  fld_type )

inline

Member Data Documentation

base_columns_map

MY_BITMAP Value_generator::base_columns_map

Bitmap records base columns which a generated column depends on.

expr_item

Item* Value_generator::expr_item {nullptr}

Item representing the generation expression.

This is non-NULL for every Field of a TABLE, if that field is a generated column. Contrast this with the Field of a TABLE_SHARE, which has expr_item==NULL even if it's a generated column; that makes sense, as an Item tree cannot be shared.

expr_str

LEX_STRING Value_generator::expr_str {nullptr, 0}

Text of the expression.

Used in only one case:

• the text read from the DD is put into the Value_generator::expr_str of the Field of the TABLE_SHARE; then this expr_str is used as source to produce expr_item for the Field of every TABLE derived from this TABLE_SHARE.

field_type

enum_field_types Value_generator::field_type {MYSQL_TYPE_INVALID}

private

Real field type.

item_list

Item* Value_generator::item_list {nullptr}

List of all items created when parsing and resolving generated expression.

m_backup_binlog_stmt_flags

uint32 Value_generator::m_backup_binlog_stmt_flags {0}

Bit field indicating the type of statement for binary logging.

It needs to be saved because this is determined only once when it is parsed but it needs to be set on the lex for each statement that uses this value generator. And since unpacking is done once on table open, it will be set for the rest of the statements in bind_value_generator_to_fields.

num_non_virtual_base_cols

uint Value_generator::num_non_virtual_base_cols {0}

private

How many non-virtual base columns in base_columns_map.

stored_in_db

bool Value_generator::stored_in_db {false}

private

Indicates if the field is physically stored in the database.

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

• sql/field.h
• sql/table.cc