Commit 2d425116 authored by Moayad Mardini's avatar Moayad Mardini Committed by Tim Graham
Browse files

Fixed #22349 -- Added a note clarifying `RawQuerySet` has no `__len__`. 

Thanks cdestigter for the report.
parent 38616697

AUTHORS

+1 −0
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@@ -422,6 +422,7 @@ answer newbie questions, and generally made Django that much better: 
    Javier Mansilla <javimansilla@gmail.com>

    masonsimon+django@gmail.com

    Manuzhai

    Moayad Mardini <moayad.m@gmail.com>

    Petr Marhoun <petr.marhoun@gmail.com>

    Petar Marić <http://www.petarmaric.com/>

    Nuno Mariz <nmariz@gmail.com>

docs/topics/db/sql.txt

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@@ -33,7 +33,8 @@ return model instances: 


This method takes a raw SQL query, executes it, and returns a

``django.db.models.query.RawQuerySet`` instance. This ``RawQuerySet`` instance

can be iterated over just like a normal QuerySet to provide object instances.

can be iterated over just like a normal

:class:`~django.db.models.query.QuerySet` to provide object instances.



This is best illustrated with an example. Suppose you have the following model::
@@ -84,6 +85,17 @@ options that make it very powerful. 
    both rows will match. To prevent this, perform the correct typecasting

    before using the value in a query.



.. warning::



    While a ``RawQuerySet`` instance can be iterated over like a normal

    :class:`~django.db.models.query.QuerySet`, ``RawQuerySet`` doesn't

    implement all methods you can use with ``QuerySet``. For example,

    ``__bool__()`` and ``__len__()`` are not defined in ``RawQuerySet``, and

    thus all ``RawQuerySet`` instances are considered ``True``. The reason

    these methods are not implemented in ``RawQuerySet`` is that implementing

    them without internal caching would be a performance drawback and adding

    such caching would be backward incompatible.



Mapping query fields to model fields

------------------------------------