text: from enum import Enum
  
  
  # override the Enum's default stringify method
  # refer: https://stackoverflow.com/questions/24487405
  Enum.__str__ = lambda self: str(self.value)
  
  
  class DBColumnType(Enum):
    bool = 'bool'
    datetime = 'datetime'
    date = 'date'
    float = 'float'
    int = 'int'
    json = 'json'
    str = 'str'
    time = 'time'
    bit = 'bit'
    bigint = 'bigint'
    #: Unix Timestamp(not pandas.Timestamp), represent seconds count from 1970/1/1 00:00:00.
    timestamp = 'timestamp'
  