Resultset row

A resultset row represents a database resultset unit, which is usually generated by executing a statement that queries the database. Using COM_STMT_EXECUTE the resultsetrow will be in binary format, others in text format.

Text resultset row

• for each column

  • string column data

The byte representation of the string according to client character collation.

Binary resultset row

• byte<1> 0x00 header

• byte<(number_of_columns + 7) / 8> NULL-Bitmap

• for each column

  • if column value is not null

    • if MYSQL_TYPE_DOUBLE type : DOUBLE Binary encoding

    • if MYSQL_TYPE_LONGLONG type : BIGINT Binary encoding

    • if MYSQL_TYPE_INTEGER type : INTEGER Binary encoding

    • if MYSQL_TYPE_MEDIUMINT type : MEDIUMINT Binary encoding

    • if MYSQL_TYPE_FLOAT type : FLOAT Binary encoding

    • if MYSQL_TYPE_SMALLINT type : SMALLINTBinary encoding

    • if MYSQL_TYPE_YEAR type : YEAR Binary encoding

    • if MYSQL_TYPE_TINYINT type : TINYINT Binary encoding

    • if MYSQL_TYPE_DATE type : DATE Binary encoding

    • if MYSQL_TYPE_TIMESTAMP type : TIMESTAMP Binary encoding

    • if MYSQL_TYPE_DATETIME type : TIMESTAMP Binary encoding

    • if MYSQL_TYPE_TIME type : TIME Binary encoding

    • if MYSQL_TYPE_NEWDECIMAL type : DECIMAL Binary encoding

    • if MYSQL_TYPE_TINY_BLOB, MYSQL_TYPE_MEDIUM_BLOB, MYSQL_TYPE_LONG_BLOB, MYSQL_TYPE_BLOB, MYSQL_TYPE_GEOMETRY,MYSQL_TYPE_STRING, MYSQL_TYPE_VARCHAR, MYSQL_TYPE_VAR_STRING): byte value

NULL-Bitmap values

The NULL-Bitmap indicates if a parameter for a column is null (one bit per parameter) beginning with the 3rd bit. NULL-bitmap size is (number_of_columns + 7) / 8.

DECIMAL Binary encoding.

DECIMAL has no fixed size, so will be encoded as string. An DECIMAL(10,2) with a value of -15.5 is stored as

06 45 49 53 46 53 48      . - 1 5 . 5 0

DOUBLE binary encoding

DOUBLE is the IEEE 754 floating-point value in Little-endian format on 8 bytes.

BIGINT binary encoding

BIGINT is the value in Little-endian format on 8 bytes. Signed is defined by the Column field detail flag.

INTEGER binary encoding

INTEGER is the value in Little-endian format on 4 bytes. Signed is defined by the Column field detail flag.

MEDIUMINT binary encoding

MEDIUMINT is similar to INTEGER binary encoding, even if MEDIUM int is 3-bytes encoded server side. (Last byte will always be 0x00).

FLOAT binary encoding

FLOAT is the IEEE 754 floating-point value in Little-endian format on 4 bytes.

SMALLINT binary encoding

SMALLINT is the value in Little-endian format on 2 bytes. Signed is defined by the Column field detail flag.

YEAR binary encoding

YEAR uses the same format as SMALLINT.

TINYINT binary encoding

TINYINT is the value of 1 byte. Signed is defined by the Column field detail flag.

DATE binary encoding

DATE uses the same format as TIMESTAMP binary encoding, with a data length of 0 for the special '0000-00-00' value and 4 for the standard year/month/day format

TIMESTAMP binary encoding

Data is encoded in 8 bytes without fractional seconds, 12 bytes with fractional seconds.

byte position	description
1	data length : 0 for special '0000-00-00 00:00:00' value. 4 with year + month + day of month only 7 for timestamps without fractional seconds 11 with fractional seconds
2-3	year on 2 bytes little-endian format
4	Month ( 1=january)
5	days of month
6	hour of day (0 if DATE type)
7	minutes (0 if DATE type)
8	secondes (0 if DATE type)
9-12	micro-second on 4 bytes little-endian format (only if data-length is > 7)

TIME binary encoding

Data is encoded in 9 bytes without fractional seconds, 13 bytes with fractional seconds.

• int<1> data length: 0 for special '00:00:00' value, 8 without fractional seconds, 12 with fractional seconds

• if data length > 0

  • int<1> 0 for positive time, 1 for negative time

  • int<4> days

  • int<1> hours

  • int<1> minutes

  • int<1> seconds

  • if data length > 8

    • int<4> microseconds

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