docs: def save_var(self, key, value, **kwargs):
      'Save one variable to the database.'
  
      # Check whether Highwall's variables table exists
      self.__check_or_create_vars_table()
  
      column_type = get_column_type(value)
      tmp = quote(self.__vars_table_tmp)
  
      self.execute(u'DROP TABLE IF EXISTS %s' % tmp, commit = False)
  
      # This is vulnerable to injection
      self.execute(u'CREATE TABLE %s (`value` %s)' % (tmp, column_type), commit = False)
  
      # This is ugly
      self.execute(u'INSERT INTO %s (`value`) VALUES (?)' % tmp, [value], commit = False)
      table = (quote(self.__vars_table), tmp)
      params = [key, column_type]
      self.execute(u'''
  INSERT OR REPLACE INTO %s (`key`, `type`, `value`)
    SELECT
      ? AS key,
      ? AS type,
      value
    FROM %s
  ''' % table, params)
      self.execute(u'DROP TABLE %s' % tmp, commit = False)
  
      self.__commit_if_necessary(kwargs)