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copied!<p>Your example seems to sit between two different ways you can go, but is currently not correct. What is happening is that you are creating two tables: Product, and Mattress, and they are completely unrelated. Regardless of the fact that Mattress subclasses Product, it is just inheriting its structure. You cannot query anything in the Product table about a mattress because a mattress is in the Mattress table.</p> <p>One way to go is to consider a Product just abstract, to be subclassed by actual products:</p> <pre><code>class Product(RandomPrimaryIdModel): class Meta: abstract=True </code></pre> <p>This will prevent a Product table from being created. Then you would directly query a mattress via: <code>Mattress.objects.filter()</code></p> <p>But this seems a bit limiting in terms of introducing many types of products, and having to manage different tables for them. The other way to go is to use a Product table, but use generic relations to support attaching any type of other table as a content object:</p> <pre><code>from django.db import models from django.contrib.contenttypes.models import ContentType from django.contrib.contenttypes import generic class Product(RandomPrimaryIdModel): feature1 = models.CharField(max_length=20, blank=True, null=True) feature2 = models.CharField(max_length=20, blank=True, null=True) feature3 = models.CharField(max_length=20, blank=True, null=True) content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') </code></pre> <p>With this, you would be able to set the <code>content_object</code> to be a Mattress instance. You can then use the ContentType to query:</p> <pre><code>p_type = ContentType.objects.get(name="mattress") Product.objects.filter(content_type=p_type) </code></pre>

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