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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/db-api.txt | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/docs/db-api.txt b/docs/db-api.txt index 5cb5e4c983..20a319740e 100644 --- a/docs/db-api.txt +++ b/docs/db-api.txt @@ -596,7 +596,7 @@ related ``Person`` *and* the related ``City``:: Note that ``select_related()`` does not follow foreign keys that have ``null=True``. -Usually, using ``select_related()`` can vastly improve performance since your +Usually, using ``select_related()`` can vastly improve performance because your app can avoid many database calls. However, in situations with deeply nested sets of relationships ``select_related()`` can sometimes end up following "too many" relations, and can generate queries so large that they end up being slow. @@ -608,6 +608,8 @@ follow:: b = Book.objects.select_related(depth=1).get(id=4) p = b.author # Doesn't hit the database. c = p.hometown # Requires a database call. + +The ``depth`` argument is new in the Django development version. ``extra(select=None, where=None, params=None, tables=None)`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |