Meta data of a column. More...

Public Types
enum	FieldType { SINT = 1 , UINT = 2 , DOUBLE = 5 , FLOAT = 6 , BYTES = 7 , TIME = 10 , DATETIME = 12 , SET = 15 , ENUM = 16 , BIT = 17 , DECIMAL = 18 }

Public Attributes
required FieldType	type = 1
	datatype of the field in a row More...

optional bytes	name = 2
	name of the column More...

optional bytes	original_name = 3
	name of the column before an alias was applied More...

optional bytes	table = 4
	name of the table the column originates from More...

optional bytes	original_table = 5
	name of the table the column originates from before an alias was applied More...

optional bytes	schema = 6
	schema the column originates from More...

optional bytes	catalog = 7
	catalog the schema originates from More...

optional uint64	collation = 8

optional uint32	fractional_digits = 9
	displayed factional decimal digits for floating point and fixed point numbers More...

optional uint32	length = 10
	maximum count of displayable characters of .type More...

optional uint32	flags = 11
	`.type` specific flags More...

optional uint32	content_type = 12
	a hint about the higher-level encoding of a BYTES field More...

ServerMessages::Type	server_message_id = RESULTSET_COLUMN_META_DATA

Detailed Description

Meta data of a column.

Note: The encoding used for the different bytes fields in the meta data is externally controlled. See also: https://dev.mysql.com/doc/refman/5.0/en/charset-connection.html

Note: The server may not set the original_{table|name} fields if they are equal to the plain {table|name} field.

Note: A client has to reconstruct it like:
if .original_name is empty and .name is not empty:

.original_name = .name

if .original_table is empty and .table is not empty:

.original_table = .table

Note: Compact metadata format can be requested by the client. In that case, only .type is set and all other fields are empty.

Expected data type of Mysqlx::Resultset::Row per SQL Type for non-NULL values:

SQL Type	.type	.length	.frac_dig	.flags	.charset
TINY	SINT	x
TINY UNSIGNED	UINT	x		x
SHORT	SINT	x
SHORT UNSIGNED	UINT	x		x
INT24	SINT	x
INT24 UNSIGNED	UINT	x		x
INT	SINT	x
INT UNSIGNED	UINT	x		x
LONGLONG	SINT	x
LONGLONG UNSIGNED	UINT	x		x
DOUBLE	DOUBLE	x	x	x
FLOAT	FLOAT	x	x	x
DECIMAL	DECIMAL	x	x	x
VARCHAR,CHAR,...	BYTES	x		x	x
GEOMETRY	BYTES
TIME	TIME	x
DATE	DATETIME	x
DATETIME	DATETIME	x
YEAR	UINT	x		x
TIMESTAMP	DATETIME	x
SET	SET				x
ENUM	ENUM				x
NULL	BYTES
BIT	BIT	x

Note: The SQL "NULL" value is sent as an empty field value in Mysqlx::Resultset::Row.

Tip: The protobuf encoding of primitive data types is described in https://developers.google.com/protocol-buffers/docs/encoding

SINT
- .length
  Maximum number of displayable decimal digits (including minus sign) of the type.
  Note
  The valid range is 0-255, but usually you'll see 1-20.
  
  SQL Type Maximum Digits per Type
  
  TINY SIGNED 4
  
  SHORT SIGNED 6
  
  INT24 SIGNED 8
  
  INT SIGNED 11
  
  LONGLONG SIGNED 20
  
  Tip
  Definition of M are in https://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html.
- value
  Variable length encoded signed 64 integer.
UINT
- .flags & 1 (zerofill)
  The client has to left pad with 0's up to .length.
- .length
  Maximum number of displayable decimal digits of the type.
  Note
  The valid range is 0-255, but usually you'll see 1-20.
  
  SQL Type max digits per type
  
  TINY UNSIGNED 3
  
  SHORT UNSIGNED 5
  
  INT24 UNSIGNED 8
  
  INT UNSIGNED 10
  
  LONGLONG UNSIGNED 20
  
  Tip
  Definition of M are in https://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html.
- value
  Variable length encoded unsigned 64 integer.
BIT
- .length
  Maximum number of displayable binary digits.
  Note
  The valid range for M of the BIT type is 1 - 64.
  
  Tip
  https://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html
- value
  Variable length encoded unsigned 64 integer.
DOUBLE
- .length
  Maximum number of displayable decimal digits (including the decimal point and .fractional_digits).
- .fractional_digits
  Maximum number of displayable decimal digits following the decimal point.
- value
  Encoded as protobuf's 'double'.
FLOAT
- .length
  Maximum number of displayable decimal digits (including the decimal point and .fractional_digits).
- .fractional_digits
  Maximum number of displayable decimal digits following the decimal point.
- value
  Encoded as protobuf's 'float'.

BYTES, ENUM

Note

BYTES is used for all opaque byte strings that may have a charset:

TINYBLOB, BLOB, MEDIUMBLOB, LONGBLOB
TINYTEXT, TEXT, MEDIUMTEXT, LONGTEXT
VARCHAR, VARBINARY
CHAR, BINARY
ENUM

.length
Maximum length of characters of the underlying type.

.flags & 1 (rightpad)
If the length of the field is less than .length, the receiver is supposed to add padding characters to the right end of the string. If the .charset is "binary", the padding character is 0x00, otherwise it is a space character as defined by that character set.

SQL Type	.length	.charset	.flags
TINYBLOB	256	binary
BLOB	65535	binary
VARCHAR(32)	32	utf8
VARBINARY(32)	32	utf8_bin
BINARY(32)	32	binary	rightpad
CHAR(32)	32	utf8	rightpad

value Sequence of bytes with added one extra 0x00 byte at the end. To obtain the original string, the extra 0x00 should be removed. The length of the string can be acquired with protobuf's field length() method:

length of sequence-of-bytes = length-of-field - 1
Note
The extra byte allows to distinguish between a NULL and empty byte sequence.

TIME

A time value.
- value
  The following bytes sequence:
  
  negate [ hour [ minutes [ seconds [ useconds ]]]]
  - negate - one byte, should be one of: 0x00 for "+", 0x01 for "-"
  - hour - optional variable length encoded unsigned64 value for the hour
  - minutes - optional variable length encoded unsigned64 value for the minutes
  - seconds - optional variable length encoded unsigned64 value for the seconds
  - useconds - optional variable length encoded unsigned64 value for the microseconds
    
    Tip
    The protobuf encoding in https://developers.google.com/protocol-buffers/docs/encoding.
    
    Note
    Hour, minutes, seconds, and useconds are optional if all the values to the right are 0.
    
    Example: 0x00 -> +00:00:00.000000
DATETIME

A date or date and time value.
- value
  A sequence of variants, arranged as follows:
  
  | year | month | day | [ | hour | [ | minutes | [ | seconds | [ | useconds | ]]]]
  - year - variable length encoded unsigned64 value for the year
  - month - variable length encoded unsigned64 value for the month
  - day - variable length encoded unsigned64 value for the day
  - hour - optional variable length encoded unsigned64 value for the hour
  - minutes - optional variable length encoded unsigned64 value for the minutes
  - seconds - optional variable length encoded unsigned64 value for the seconds
  - useconds - optional variable length encoded unsigned64 value for the microseconds
    Note
    Hour, minutes, seconds, useconds are optional if all the values to the right are 0.
- .flags
  
  Name Position
  
  is_timestamp 1
DECIMAL

An arbitrary length number. The number is encoded as a single byte indicating the position of the decimal point followed by the Packed BCD encoded number. Packed BCD is used to simplify conversion to and from strings and other native arbitrary precision math data types. See also: packed BCD in https://en.wikipedia.org/wiki/Binary-coded_decimal
- .length Maximum number of displayable decimal digits (excluding the decimal point and sign, but including .fractional_digits).
  Note
  Should be in the range of 1 - 65.
- .fractional_digits The decimal digits to display out of length.
  Note
  Should be in the range of 0 - 30.
  
  value The following bytes sequence:
  
  scale | BCD+ sign [0x00]?
  - scale - 8bit scale value (number of decimal digit after the '.')
  - BCD - BCD encoded digits (4 bits for each digit)
  - sign - sign encoded on 4 bits (0xc = "+", 0xd = "-")
  - 0x0 - last 4bits if length(digits) % 2 == 0
  Example: x04 0x12 0x34 0x01 0xd0 -> -12.3401
SET

A list of strings representing a SET of values.
- value
  A sequence of 0 or more of protobuf's bytes (length prepended octets) or one of the special sequences with a predefined meaning listed below.
  
  Example (length of the bytes array shown in brackets):
  - [0] - the NULL value
  - [1] 0x00 - a set containing a blank string ''
  - [1] 0x01 - this would be an invalid value, but is to be treated as the empty set
  - [2] 0x01 0x00 - a set with a single item, which is the '0' character
  - [8] 0x03 F O O 0x03 B A R - a set with 2 items: FOO,BAR

Member Enumeration Documentation

◆ FieldType

enum Mysqlx::Resultset::ColumnMetaData::FieldType

Enumerator
SINT
UINT
DOUBLE
FLOAT
BYTES
TIME
DATETIME
SET
ENUM
BIT
DECIMAL

Member Data Documentation

◆ catalog

optional bytes Mysqlx::Resultset::ColumnMetaData::catalog = 7

catalog the schema originates from

Note: As there is currently no support for catalogs in MySQL, don't expect this field to be set. In the MySQL C/S protocol the field had the value def all the time

◆ collation

optional uint64 Mysqlx::Resultset::ColumnMetaData::collation = 8

◆ content_type

optional uint32 Mysqlx::Resultset::ColumnMetaData::content_type = 12

a hint about the higher-level encoding of a BYTES field

Type	Value	Description
BYTES	0x0001	GEOMETRY (WKB encoding)
BYTES	0x0002	JSON (text encoding)
BYTES	0x0003	XML (text encoding)

Note: This list isn't comprehensive. As a guideline: the field's value is expected to pass a validator check on client and server if this field is set. If the server adds more internal data types that rely on BLOB storage like image manipulation, seeking into complex types in BLOBs, and more types will be added

◆ flags

optional uint32 Mysqlx::Resultset::ColumnMetaData::flags = 11

.type specific flags

Type	Value	Description
UINT	0x0001	zerofill
DOUBLE	0x0001	unsigned
FLOAT	0x0001	unsigned
DECIMAL	0x0001	unsigned
BYTES	0x0001	rightpad

Value	Description
0x0010	NOT_NULL
0x0020	PRIMARY_KEY
0x0040	UNIQUE_KEY
0x0080	MULTIPLE_KEY
0x0100	AUTO_INCREMENT

default: 0

◆ fractional_digits

optional uint32 Mysqlx::Resultset::ColumnMetaData::fractional_digits = 9

displayed factional decimal digits for floating point and fixed point numbers

◆ length

optional uint32 Mysqlx::Resultset::ColumnMetaData::length = 10

maximum count of displayable characters of .type

◆ name

optional bytes Mysqlx::Resultset::ColumnMetaData::name = 2

name of the column

◆ original_name

optional bytes Mysqlx::Resultset::ColumnMetaData::original_name = 3

name of the column before an alias was applied

◆ original_table

optional bytes Mysqlx::Resultset::ColumnMetaData::original_table = 5

name of the table the column originates from before an alias was applied

◆ schema

optional bytes Mysqlx::Resultset::ColumnMetaData::schema = 6

schema the column originates from

◆ server_message_id

ServerMessages::Type Mysqlx::Resultset::ColumnMetaData::server_message_id = RESULTSET_COLUMN_META_DATA

◆ table

optional bytes Mysqlx::Resultset::ColumnMetaData::table = 4

name of the table the column originates from

◆ type

required FieldType Mysqlx::Resultset::ColumnMetaData::type = 1

datatype of the field in a row

The documentation for this struct was generated from the following file:

plugin/x/protocol/protobuf/mysqlx_resultset.proto

SQL Type	Maximum Digits per Type
TINY SIGNED	4
SHORT SIGNED	6
INT24 SIGNED	8
INT SIGNED	11
LONGLONG SIGNED	20

Public Types

Public Attributes