Query methods — PyGreSQL 5.0 documentation

# Query methods

class `pg.` `Query`

The `Query` object returned by `Connection.query()` and `DB.query()` provides the following methods for accessing the results of the query:

## getresult – get query values as list of tuples

`Query.` `getresult`()

  Get query values as list of tuples

  Returns: | result values as a list of tuples
  Return type: | list
  Raises: | TypeError – too many (any) parameters MemoryError – internal memory error

This method returns the list of the values returned by the query. More information about this result may be accessed using `Query.listfields()`, `Query.fieldname()` and `Query.fieldnum()` methods.

Note that since PyGreSQL 5.0 this will return the values of array type columns as Python lists.

## dictresult – get query values as list of dictionaries

`Query.` `dictresult`()

  Get query values as list of dictionaries

  Returns: | result values as a list of dictionaries
  Return type: | list
  Raises: | TypeError – too many (any) parameters MemoryError – internal memory error

This method returns the list of the values returned by the query with each tuple returned as a dictionary with the field names used as the dictionary index.

Note that since PyGreSQL 5.0 this will return the values of array type columns as Python lists.

## namedresult – get query values as list of named tuples

`Query.` `namedresult`()

  Get query values as list of named tuples

  Returns: | result values as a list of named tuples
  Return type: | list
  Raises: | TypeError – too many (any) parameters TypeError – named tuples not supported MemoryError – internal memory error

This method returns the list of the values returned by the query with each row returned as a named tuple with proper field names.

Note that since PyGreSQL 5.0 this will return the values of array type columns as Python lists.

New in version 4.1.

## listfields – list fields names of previous query result

`Query.` `listfields`()

  List fields names of previous query result

  Returns: | field names
  Return type: | list
  Raises: | TypeError – too many parameters

This method returns the list of names of the fields defined for the query result. The fields are in the same order as the result values.

## fieldname, fieldnum – field name/number conversion

`Query.` `fieldname`(num)

  Get field name from its number

  Parameters: | num (int) – field number
  Returns: | field name
  Return type: | str
  Raises: | TypeError – invalid connection, bad parameter type, or too many parameters ValueError – invalid field number

This method allows to find a field name from its rank number. It can be useful for displaying a result. The fields are in the same order as the result values.

`Query.` `fieldnum`(name)

  Get field number from its name

  Parameters: | name (str) – field name
  Returns: | field number
  Return type: | int
  Raises: | TypeError – invalid connection, bad parameter type, or too many parameters ValueError – unknown field name

This method returns a field number from its name. It can be used to build a function that converts result list strings to their correct type, using a hardcoded table definition. The number returned is the field rank in the result values list.

## ntuples – return number of tuples in query object

`Query.` `ntuples`()

  Return number of tuples in query object

  Returns: | number of tuples in `Query`
  Return type: | int
  Raises: | TypeError – Too many arguments.

This method returns the number of tuples found in a query.