MySQL Field Class Hierarchy

每天睁眼看几遍，背下来就行了。

Field (abstract)

|

+--Field_bit

| +--Field_bit_as_char

|

+--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

| +--Field_year

|

+--Field_str (abstract)

| +--Field_longstr

| | +--Field_string

| | +--Field_varstring

| | +--Field_blob

| | +--Field_geom

| |

| +--Field_null

| +--Field_enum

| +--Field_set

|

+--Field_temporal (abstract)

+--Field_time_common (abstract)

| +--Field_time

| +--Field_timef

|

+--Field_temporal_with_date (abstract)

+--Field_newdate

+--Field_temporal_with_date_and_time (abstract)

+--Field_timestamp

+--Field_datetime

+--Field_temporal_with_date_and_timef (abstract)

+--Field_timestampf

+--Field_datetimef