Django content type model design and requirements

Question

I have three different models (Job, Tender, News).

class Tender(models.Model):
    title = models.CharField(max_length=256)
    description = models.TextField()
    department = models.CharField(max_length=50)
    tags = models.ManyToManyField(Tag)
    pub_date = models.DateTimeField(default=timezone.now)

class Job(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL)
    title = models.CharField(max_length=256)
    qualification = models.CharField(max_length=256)
    employer = models.CharField(max_length=50)
    salary = models.IntegerField()    
    tags = models.ManyToManyField(Tag)
    pub_date = models.DateTimeField(default=timezone.now)

class News(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL)
    title = models.CharField(max_length=150)
    body = models.TextField()
    tags = models.ManyToManyField(Tag)
    pub_date = models.DateTimeField(default=timezone.now)

Now I would like to make another model ( class Post), so that whenever a new object is created (job or tender or news), a new post object should be created, basically this will be done using signals.

Now with this post class

1. I would like to filter using the user who created the job/tender/news object.
2. Also filter using the tags which was used in the job/tender/news object.
3. Order by pub_date.

I am very new to django's content type, and confused what fields will be required. I only know for sure that this three fields are required, content type, object id and content object.

class Post(models.Model):
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

But to get the functionality that I want (i.e. filter and order by), do I have to add user, tags and pub_date field to the Post class?

Answer 1

From Django documentation:

Due to the way GenericForeignKey is implemented, you cannot use such fields directly with filters (filter() and exclude(), for example) via the database API. Because a GenericForeignKey isn’t a normal field object, these examples will not work:

I believe the short answer is you will need to include user, tags and pub_date or perhaps better would be links to the models through ForeignKey.