谁能让我简单地理解

    def single(request,slug):
            pro = products.objects.get(slug=slug)
            images=productImage.objects.filter(product=pro)
            template = 'products.html'
            context = {'pro': pro,'images':images}
            return render(request, template, context)

class products(models.Model):
    title = models.CharField(max_length=120)
    desc = models.TextField()
    price = models.DecimalField(max_digits=10, decimal_places=2, default=29.99)
    sales_price = models.DecimalField(max_digits=10, decimal_places=2, blank=False,         null=False, default=0)
    slug = models.SlugField(unique=True)
    timestamp = models.DateTimeField(auto_now_add=True, auto_now=False)
    update = models.DateTimeField(auto_now_add=False, auto_now=True)
    active = models.BooleanField(default=True)

    def __str__(self):
        return self.title

    def get_price(self):
        return self.price

    def get_absolute_url(self):
        return reverse("single", kwargs={"slug": self.slug})


class productImage(models.Model):
    product = models.ForeignKey(products, on_delete=models.CASCADE)
    image = models.ImageField(upload_to='images/')
    featured = models.BooleanField(default=False)
    Thumbnail = models.BooleanField(default=False)
    active = models.BooleanField(default=True)
    update = models.DateTimeField(auto_now_add=False, auto_now=True)

    def __str__(self):`enter code here`
        return self.product.title   

pro = products.objects.get（slug = slug）和images = productImage.objects.filter（productt = product）的任务是什么。使用product.productImage_set.all和productImage.objects.filter（product = product）有什么区别