code: func NewTinyFieldDescriptor(nullable NullableColumn) FieldDescriptor {
  	return newFixedLengthFieldDescriptor(
  		mysql_proto.FieldType_TINY,
  		nullable,
  		1,
  		func(b []byte) interface{} { return uint64(b[0]) })
  }
docs: // This contains field descriptors for numeric types as defined by sql/field.h.
  // In particular:
  //
  // Field (abstract)
  // |
  // ...
  // |
  // +--Field_num (abstract)
  // |  |  +--Field_real (asbstract)
  // |  |     +--Field_decimal
  // |  |     +--Field_float
  // |  |     +--Field_double
  // |  |
  // |  +--Field_new_decimal
  // |  +--Field_short
  // |  +--Field_medium
  // |  +--Field_long
  // |  +--Field_longlong
  // |  +--Field_tiny
  // ...
  //
  // NOTE: Field_year is grouped with other temporal fields.
  // This returns a field descriptor for FieldType_TINY (i.e., Field_tiny).