Added note to docs/db-api.txt about 'depth' being new in Django development version
git-svn-id: http://code.djangoproject.com/svn/django/trunk@4649 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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@ -596,7 +596,7 @@ related ``Person`` *and* the related ``City``::
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Note that ``select_related()`` does not follow foreign keys that have
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``null=True``.
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Usually, using ``select_related()`` can vastly improve performance since your
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Usually, using ``select_related()`` can vastly improve performance because your
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app can avoid many database calls. However, in situations with deeply nested
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sets of relationships ``select_related()`` can sometimes end up following "too
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many" relations, and can generate queries so large that they end up being slow.
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@ -608,6 +608,8 @@ follow::
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b = Book.objects.select_related(depth=1).get(id=4)
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p = b.author # Doesn't hit the database.
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c = p.hometown # Requires a database call.
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The ``depth`` argument is new in the Django development version.
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``extra(select=None, where=None, params=None, tables=None)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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