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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/db-api.txt | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/docs/db-api.txt b/docs/db-api.txt index af5ba8ce49..e15b0b2176 100644 --- a/docs/db-api.txt +++ b/docs/db-api.txt @@ -510,12 +510,13 @@ primary key if there is no ``Meta.ordering`` specified. For example:: ...since the ``Blog`` model has no default ordering specified. -You can only order by model fields that have a single value attached to them -for each instance of the model. For example, non-relations, ``ForeignKey`` and -``OneToOneField`` fields. Explicitly, you can't order by a ``ManyToManyField`` -or a reverse ``ForeignKey`` relation. There's no naturally correct ordering -for many-valued fields and a lot of the alternatives are not psosible to -express in SQL very efficiently. +It is permissible to specify a multi-valued field to order the results by (for +example, a ``ManyToMany`` field). Normally this won't be a sensible thing to +do and it's really an advanced usage feature. However, if you know that your +queryset's filtering or available data implies that there will only be one +ordering piece of data for each of the main items you are selecting, the +ordering may well be exactly what you want to do. Use ordering on multi-valued +fields with care and make sure the results are what you expect. **New in Django development version:** If you don't want any ordering to be applied to a query, not even the default ordering, call ``order_by()`` with no |