Protocol::ColumnDefinition41:

Payload
Type	Name	Description
string<lenenc>	catalog	The catalog used. Currently always "def"
string<lenenc>	schema	schema name
string<lenenc>	table	virtual table name
string<lenenc>	org_table	physical table name
string<lenenc>	name	virtual column name
string<lenenc>	org_name	physical column name
int<lenenc>	length of fixed length fields	[0x0c]
int<2>	character_set	the column character set as defined in Character Set
int<4>	column_length	maximum length of the field
int<1>	type	type of the column as defined in enum_field_types
int<2>	flags	Flags as defined in Column Definition Flags
int<1>	decimals	max shown decimal digits: 0x00 for integers and static strings 0x1f for dynamic strings, double, float 0x00 to 0x51 for decimals

Protocol::ColumnDefinition320:

Payload
Type	Name	Description
string<lenenc>	table	Table name
string<lenenc>	name	Column name
int<lenenc>	length of type field	[01]
int<1>	type	type of the column as defined in enum_field_types
if capabilities & CLIENT_LONG_FLAG {
int<lenenc>	length of flags + decimals fields	[03]
int<2>	flags	Flags as defined in Column Definition Flags
int<1>	decimals	number of decimal digits
} else {
int<lenenc>	length of flags + decimals fields	[02]
int<2>	flags	Flags as defined in Column Definition Flags
int<1>	decimals	number of decimal digits
}
if command was COM_FIELD_LIST {
int<lenenc>	length of default values	[02]
string<lenenc>	default_values
}