> On Wed, Mar 11, 2009 at 9:11 PM, Alex Gaynor <alex.gay...@gmail.com>wrote:

>> On Wed, Mar 11, 2009 at 10:31 AM, Madhusudan C.S <madhusuda...@gmail.com>wrote:

>>> Hi all,
>>>      I wanted to fix this bug. I just went through the code to see what
>>> was happening. For the same sample code given in the ticket, these were my
>>> findings:

>>> The schema generated looks like this and there is no issue with it:
>>> CREATE TABLE "testapp_childmodel" (
>>>     "parentmodel_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES
>>> "testapp_parentmodel" ("id"),
>>>     "text" text NOT NULL
>>> );
>>> CREATE TABLE "testapp_parentmodel" (
>>>     "id" integer NOT NULL PRIMARY KEY,
>>>     "slug" varchar(50) NOT NULL
>>> );
>>> CREATE TABLE "testapp_parentmodel_links" (
>>>     "id" integer NOT NULL PRIMARY KEY,
>>>     "from_parentmodel_id" integer NOT NULL REFERENCES
>>> "testapp_parentmodel" ("id"),
>>>     "to_parentmodel_id" integer NOT NULL REFERENCES "testapp_parentmodel"
>>> ("id"),
>>>     UNIQUE ("from_parentmodel_id", "to_parentmodel_id")
>>> );

>>> CREATE INDEX "testapp_parentmodel_slug" ON "testapp_parentmodel"
>>> ("slug");

>>> I inserted test1, test2 and test3(all names being values of slug field)
>>> to ParentModel and linked test1 and test3 to test2 through links field.
>>> There seems to be no issues. Then I inserted testc1, testc2 and testc3 to
>>> ChildModel and linked testc2 and testc3 to testc1 through inherited links
>>> field. Now I can see only to links, i.e
>>> I get these results in the interactive interpreter:

>>> >>> from dummy.testapp.models import ParentModel, ChildModel
>>> >>> c1 = ChildModel.objects.get(slug='testc1')
>>> >>> c2 = ChildModel.objects.get(slug='testc2')
>>> >>> c3 = ChildModel.objects.get(slug='testc3')
>>> >>> c1.links.all()
>>> []
>>> >>> c2.links.all()
>>> [<ParentModel: testc1>]
>>> >>> c3.links.all()
>>> [<ParentModel: testc1>]

>>> This means only to links are being queried and not from links for the
>>> inherited model. I just saw how the queries are working and these are the
>>> queries constructed for c1, c2 and c3 respectively.

>>> SELECT "testapp_parentmodel"."id", "testapp_parentmodel"."slug" FROM
>>> "testapp_parentmodel" INNER JOIN "testapp_parentmodel_links" ON
>>> ("testapp_parentmodel"."id" =
>>> "testapp_parentmodel_links"."to_parentmodel_id") WHERE
>>> "testapp_parentmodel_links"."from_parentmodel_id" = 4  LIMIT 21

>>> SELECT "testapp_parentmodel"."id", "testapp_parentmodel"."slug" FROM
>>> "testapp_parentmodel" INNER JOIN "testapp_parentmodel_links" ON
>>> ("testapp_parentmodel"."id" =
>>> "testapp_parentmodel_links"."to_parentmodel_id") WHERE
>>> "testapp_parentmodel_links"."from_parentmodel_id" = 5  LIMIT 21

>>> SELECT "testapp_parentmodel"."id", "testapp_parentmodel"."slug" FROM
>>> "testapp_parentmodel" INNER JOIN "testapp_parentmodel_links" ON
>>> ("testapp_parentmodel"."id" =
>>> "testapp_parentmodel_links"."to_parentmodel_id") WHERE
>>> "testapp_parentmodel_links"."from_parentmodel_id" = 6  LIMIT 21

>>> From what I see the queries must be actually UNION of two queries which
>>> fetch data both from, "from" and "to" fields in the
>>> "testapp_parentmodel_links" table.It should look some thing like this, from
>>> what I have understood:

>>> SELECT "testapp_parentmodel"."id", "testapp_parentmodel"."slug" FROM
>>> "testapp_parentmodel" INNER JOIN "testapp_parentmodel_links" ON
>>> ("testapp_parentmodel"."id" =
>>> "testapp_parentmodel_links"."to_parentmodel_id") WHERE
>>> "testapp_parentmodel_links"."from_parentmodel_id" = 4  LIMIT 21
>>> UNION
>>> SELECT "testapp_parentmodel"."id", "testapp_parentmodel"."slug" FROM
>>> "testapp_parentmodel" INNER JOIN "testapp_parentmodel_links" ON
>>> ("testapp_parentmodel"."id" =
>>> "testapp_parentmodel_links"."from_parentmodel_id") WHERE
>>> "testapp_parentmodel_links"."to_parentmodel_id" = 4  LIMIT 21

>>> Is this an elegant approach? If so can some one help me implement this? I
>>> went through the code of QuerySet, Manager classes and other parts of
>>> django.db.models. How to go about from here? I am very keen on fixing this
>>> issue. Kindly help me.

>> This looks like it may just be a symptom of
>> http://code.djangoproject.com/ticket/10237 if I'm reading htis correctly.

>> The problem looks very similar. I applied the patch and tried out. But it
> doesn't seem to solve the problem at least for the data set I created as
> above. So problem exists some where else too. Any pointers to where it might
> be? (The query i.e being generated essentially remains the same even after
> applying the supplied patch). But manager.symmetrical which used to return
> False now correctly returns True.