From 588eeb356c7a88138fac53c3caeb705e16aa562c Mon Sep 17 00:00:00 2001 From: Malcolm Tredinnick Date: Thu, 26 Jun 2008 01:02:11 +0000 Subject: Fixed a problem when constructing complex select_related() calls. Avoids joining with the wrong tables when connecting select_related() tables to the main query. This also leads to slightly more efficient (meaning less tables are joined) SQL queries in some other cases, too. Some unnecessary tables are now trimmed that were not previously. git-svn-id: http://code.djangoproject.com/svn/django/trunk@7741 bcc190cf-cafb-0310-a4f2-bffc1f526a37 --- tests/regressiontests/queries/models.py | 36 +++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'tests/regressiontests') diff --git a/tests/regressiontests/queries/models.py b/tests/regressiontests/queries/models.py index 5af48741d6..2e84d89ea8 100644 --- a/tests/regressiontests/queries/models.py +++ b/tests/regressiontests/queries/models.py @@ -135,6 +135,24 @@ class ManagedModel(models.Model): def __unicode__(self): return self.data +# An inter-related setup with multiple paths from Child to Detail. +class Detail(models.Model): + data = models.CharField(max_length=10) + +class MemberManager(models.Manager): + def get_query_set(self): + return super(MemberManager, self).get_query_set().select_related("details") + +class Member(models.Model): + name = models.CharField(max_length=10) + details = models.OneToOneField(Detail, primary_key=True) + + objects = MemberManager() + +class Child(models.Model): + person = models.OneToOneField(Member, primary_key=True) + parent = models.ForeignKey(Member, related_name="children") + __test__ = {'API_TESTS':""" >>> t1 = Tag(name='t1') @@ -720,5 +738,23 @@ appropriately. >>> Report.objects.values_list("creator__extra__info", flat=True).order_by("name") [u'e1', u'e2', None] +Similarly for select_related(), joins beyond an initial nullable join must +use outer joins so that all results are included. +>>> Report.objects.select_related("creator", "creator__extra").order_by("name") +[, , ] + +When there are multiple paths to a table from another table, we have to be +careful not to accidentally reuse an inappropriate join when using +select_related(). We used to return the parent's Detail record here by mistake. + +>>> d1 = Detail.objects.create(data="d1") +>>> d2 = Detail.objects.create(data="d2") +>>> m1 = Member.objects.create(name="m1", details=d1) +>>> m2 = Member.objects.create(name="m2", details=d2) +>>> c1 = Child.objects.create(person=m2, parent=m1) +>>> obj = m1.children.select_related("person__details")[0] +>>> obj.person.details.data +u'd2' + """} -- cgit v1.3