text: import datetime
  
  from .base import Database
  
  
  class InsertVar:
      """
      A late-binding cursor variable that can be passed to Cursor.execute
      as a parameter, in order to receive the id of the row created by an
      insert statement.
      """
      types = {
          'AutoField': int,
          'BigAutoField': int,
          'SmallAutoField': int,
          'IntegerField': int,
          'BigIntegerField': int,
          'SmallIntegerField': int,
          'PositiveBigIntegerField': int,
          'PositiveSmallIntegerField': int,
          'PositiveIntegerField': int,
          'FloatField': Database.NATIVE_FLOAT,
          'DateTimeField': Database.TIMESTAMP,
          'DateField': Database.Date,
          'DecimalField': Database.NUMBER,
      }
  
      def __init__(self, field):
          internal_type = getattr(field, 'target_field', field).get_internal_type()
          self.db_type = self.types.get(internal_type, str)
          self.bound_param = None
  
      def bind_parameter(self, cursor):
          self.bound_param = cursor.cursor.var(self.db_type)
          return self.bound_param
  
      def get_value(self):
          return self.bound_param.getvalue()
  
  
  class Oracle_datetime(datetime.datetime):
      """
      A datetime object, with an additional class attribute
      to tell cx_Oracle to save the microseconds too.
      """
      input_size = Database.TIMESTAMP
  
      @classmethod
      def from_datetime(cls, dt):
          return Oracle_datetime(
              dt.year, dt.month, dt.day,
              dt.hour, dt.minute, dt.second, dt.microsecond,
          )
  
  
  class BulkInsertMapper:
      BLOB = 'TO_BLOB(%s)'
      CLOB = 'TO_CLOB(%s)'
      DATE = 'TO_DATE(%s)'
      INTERVAL = 'CAST(%s as INTERVAL DAY(9) TO SECOND(6))'
      NUMBER = 'TO_NUMBER(%s)'
      TIMESTAMP = 'TO_TIMESTAMP(%s)'
  
      types = {
          'AutoField': NUMBER,
          'BigAutoField': NUMBER,
          'BigIntegerField': NUMBER,
          'BinaryField': BLOB,
          'BooleanField': NUMBER,
          'DateField': DATE,
          'DateTimeField': TIMESTAMP,
          'DecimalField': NUMBER,
          'DurationField': INTERVAL,
          'FloatField': NUMBER,
          'IntegerField': NUMBER,
          'NullBooleanField': NUMBER,
          'PositiveBigIntegerField': NUMBER,
          'PositiveIntegerField': NUMBER,
          'PositiveSmallIntegerField': NUMBER,
          'SmallAutoField': NUMBER,
          'SmallIntegerField': NUMBER,
          'TextField': CLOB,
          'TimeField': TIMESTAMP,
      }
  
  
  def dsn(settings_dict):
      if settings_dict['PORT']:
          host = settings_dict['HOST'].strip() or 'localhost'
          return Database.makedsn(host, int(settings_dict['PORT']), settings_dict['NAME'])
      return settings_dict['NAME']
  