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POIssue with models/manager to organize a query
 

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  1. POIssue with models/manager to organize a query
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    <p>I have an application to count the number of access to an object for each website in a same database.</p> <pre><code>class SimpleHit(models.Model): """ Hit is the hit counter of a given object """ content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') site = models.ForeignKey(Site) hits_total = models.PositiveIntegerField(default=0, blank=True) [...] class SimpleHitManager(models.Manager): def get_query_set(self): print self.model._meta.fields qset = super(SimpleHitManager, self).get_query_set() qset = qset.filter(hits__site=settings.SITE_ID) return qset class SimpleHitBase(models.Model): hits = generic.GenericRelation(SimpleHit) objects = SimpleHitManager() _hits = None def _db_get_hits(self, only=None): if self._hits == None: try: self._hits = self.hits.get(site=settings.SITE_ID) except SimpleHit.DoesNotExist: self._hits = SimpleHit() return self._hits @property def hits_total(self): return self._db_get_hits().hits_total [...] class Meta: abstract = True </code></pre> <p>And I have a model like:</p> <pre><code>class Model(SimpleHitBase): name = models.CharField(max_length=255) url = models.CharField(max_length=255) rss = models.CharField(max_length=255) creation = AutoNowAddDateTimeField() update = AutoNowDateTimeField() </code></pre> <p>So, my problem is this one: when I call <code>Model.objects.all()</code>, I would like to have one request for the SQL (not two). In this case: one for Model in order to have information and one for the hits in order to have the counter (hits_total). This is because I cannot call directly <code>hits.hits_total</code> (due to SITE_ID?). I have tried <code>select_related</code>, but it seems to do not work...</p> <p>Question: - How can I add column automatically like <code>(SELECT hits.hits_total, model.* FROM [...])</code> to the queryset? - Or use a functional <code>select_related</code> with my models?</p> <p>I want this model could be plugable on all other existing model.</p>
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    1. USVadim Kotov
    1. USActi67
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