class Blog(models.Model):    name = models.CharField(max_length=100)    tagline = models.TextField()    def __unicode__(self):        return self.nameclass Author(models.Model):    name = models.CharField(max_length=50)    email = models.EmailField()    def __unicode__(self):        return self.nameclass Entry(models.Model):    blog = models.ForeignKey(Blog)    headline = models.CharField(max_length=255)    body_text = models.TextField()    pub_date = models.DateTimeField()    mod_date = models.DateTimeField()    authors = models.ManyToManyField(Author)    n_comments = models.IntegerField()    n_pingbacks = models.IntegerField()    rating = models.IntegerField()    def __unicode__(self):        return self.headline

>>> from blog.models import Blog>>> b = Blog(name=‘Beatles Blog‘, tagline=‘All the latest Beatles news.‘)>>> b.save()

>>> from blog.models import Entry>>> entry = Entry.objects.get(pk=1)>>> cheese_blog = Blog.objects.get(name="Cheddar Talk")>>> entry.blog = cheese_blog>>> entry.save()>>> from blog.models import Author>>> joe = Author.objects.create(name="Joe")>>> entry.authors.add(joe)>>> john = Author.objects.create(name="John")>>> paul = Author.objects.create(name="Paul")>>> george = Author.objects.create(name="George")>>> ringo = Author.objects.create(name="Ringo")>>> entry.authors.add(john, paul, george, ringo)

>>> Blog.objects<django.db.models.manager.Manager object at ...>>>> b = Blog(name=‘Foo‘, tagline=‘Bar‘)>>> b.objectsTraceback:    ...AttributeError: "Manager isn‘t accessible via Blog instances."

>>> all_entries = Entry.objects.all()

Entry.objects.filter(pub_date__year=2006)

>>> Entry.objects.filter(...     headline__startswith=‘What‘... ).exclude(...     pub_date__gte=datetime.now()... ).filter(...     pub_date__gte=datetime(2005, 1, 1)... )

>>> one_entry = Entry.objects.get(pk=1)

lt：Less than.                                                          lte：Less than or equal to.