def find_by_primary_key(self, key_fields, field_list=None):
'''
:param key_fields: The list with the values for the key_columns, in order, to use to find a record.
:param field_list: A subset of the fields of the record to return.
:return: None, or a dictionary containing the requested fields for the record identified
by the key.
'''
if Helper.is_empty(self._data['key_columns']):
self._logger.error('Table has no primary keys')
raise Exception
if not Helper.are_key_fields_valid(key_fields,
self._data['key_columns']):
self._logger.error('Key fields are not valid')
raise Exception
template = Helper.convert_key_fields_to_template(
key_fields, self._data['key_columns'])
result = self.find_by_template(template, field_list, 1)
if Helper.is_empty(result):
return None
return result[0]
def delete_by_key(self, key_fields):
'''
Deletes the record that matches the key.
:param template: A template.
:return: A count of the rows deleted.
'''
if Helper.is_empty(self._data['key_columns']):
self._logger.error('Table has no primary keys')
raise Exception
if not Helper.are_key_fields_valid(key_fields,
self._data['key_columns']):
self._logger.error('Key fields are not valid')
raise Exception
template = Helper.convert_key_fields_to_template(
key_fields, self._data['key_columns'])
return self.delete_by_template(template)
def update_by_key(self, key_fields, new_values):
'''
:param key_fields: List of value for the key fields.
:param new_values: A dict of field:value to set for updated row.
:return: Number of rows updated.
'''
if Helper.is_empty(self._data['key_columns']):
self._logger.error('Table has no primary keys')
raise Exception
if not Helper.are_key_fields_valid(key_fields,
self._data['key_columns']):
self._logger.error('Key fields are not valid')
raise Exception
if Helper.is_empty(new_values):
return 0
template = Helper.convert_key_fields_to_template(
key_fields, self._data['key_columns'])
return self.update_by_template(template, new_values)