For a better reading experience, check out [this article on my website.](https://hakibenita.com/all-you-need-to-know-about-prefetching-in-django)

I have recently worked on a ticket ordering system for a conference. It was very important for the customer to see a table of orders including a column with a list of program names in each order:

![](https://hackernoon.com/hn-images/0*Xu_3zwEwz8TV-BO9.)

The models looked (roughly) like this:

class **Program**(models.Model):  
    name = models.CharField(max\_length=20)  
  

class **Price**(models.Model):  
    program = models.ForeignKey(Program)  
    from\_date = models.DateTimeField()  
    to\_date = models.DateTimeField()  
  

class **Order**(models.Model):  
    state = models.CharField(max\_length=20)  
    items = models.ManyToManyField(Price)

*   **Program** is a session, lecture or a conference day.
*   Prices can change over time so we used a model called **Price**, modeled as a [type 2 slowly changing dimension](https://en.wikipedia.org/wiki/Slowly_changing_dimension#Type_2:_add_new_row) (SCD) that represents the price of a program at a certain time.
*   User’s can register to one or more programs. Each item in an **Order** is a program price at the time the order was made.

### Before we start

Throughout this article we are going to monitor the queries executed by Django. To log the queries add the following to the `LOGGING` settings in `settings.py`:

LOGGING = {  
      
    ...     
      
    'loggers': {  
        **'django.db.backends': {  
            'level': 'DEBUG',  
        },**  
    },  
}

![](https://hackernoon.com/hn-images/1*e2p7KTk1KzOHNuZ-td-9HA.jpeg)

Let’s see you trying to find an image related to prefetching…

All you need to know about prefetching in Django

Too Long; Didn't Read

@hakibenita

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