One thing that annoy me when using raw query in Python is how the returned value is not “easy to remember”. Look at this query:

import sqlite3
con = sqlite3.connect("library.sqlite3")
query = "SELECT id, isbn, title FROM books"
con = con.execute(query)
rows = con.fetchall()

To print the returned value I must remember the index of each field:

for r in rows:
	print(f"{r[0]} - {r[1]} - {r[2]}")

# index 0 = id
# index 1 = isbn
# index 2 = title

1 - 1234567890 - Book 1 by Author 1
2 - 2345678901 - Book 1 by Author 1
3 - 3456789012 - Book 1 by Author 1
4 - 4567890123 - Book 1 by Author 2
5 - 5678901234 - Book 1 by Author 2

And if you think it’s only coming from sqlite, you’re wrong. I tried PostgreSQL with psycopg and it has same behavior:

Several days ago, I heard a joke:

You don’t need Mongo, PostgreSQL is enough.

So… let’s try it!

Scopes

Before we move forward, let’s set the scope of this test. In my experience, the use cases where I used Mongo are:

• Store raw information coming from request/response, e.g. webhook, API call, etc.

• Store personalized config with JSON structure.

So we will try to use these cases using json and jsonb column in PostgreSQL.

When I write code in Django for the first time, I feel mesmerized by class-based views (CBV), especially the generic views. Look at this CBV example using Django REST Framework:

# serializer.py
class PostSerializer(serializers.ModelSerializer):
    class Meta:
        model = Post
        fields = '__all__'
        
  # views
  class PostListCreate(ListCreateAPIView):
     serializer_class = PostSerializer
     queryset = Post.objects.all()
     
 class PostEdit(RetrieveUpdateDestroyAPIView):
    serializer_class = PostSerializer
    queryset = Post.objects.all()

With this simple code, I already built full CRUD functionality. This code already supports:

Usually when working with Django ORM and want to update data, there are two patterns I always use: .save() and .update().

When using .save(), the code becomes like this:

model = Model.objects.get(id=1)
model.field = val
model.save()

This code will act like this:

• Run clean() on Django model
• Run the actual query
• Run related signal(s)

Using .update()

When using .update(), usually it’s to change multiple data. So instead of model instance, we use queryset instance.

I tried typehint in python and i didn’t like it, especially when working in legacy code, and then i move to other project, wrote golang code, feels good with the type, want to imitate the type in python and yes i visited again the typehint.

Expectation

Before we move forward, I must set expectation to myself. The default Python is dynamic typing, so it will not smooth like Go. Why? Let’s take a look in this code: