Document vs SQL Database

#db #database #SQL #NoSQL

Here is my amateur opinion on choosing between a document database like CouchDB or MongoDB vs a sequel database like PostgreSQL or MariaDB

Which one should I choose?

Is your data simple and the schema needs to be flexible? Choose a Document DB

Does your data have multiple relationships that link it together? Choose a SQL DB

SQL

PRO: for data that you want to relate many times over in many different ways.
CON: updating schemas can be a delicate process

DOCUMENT:

PRO: very quick to write and easy to understand. Also updating schema is a breeze
CON: becomes very verbos when wanting to link different parts together.

I'd say use document db if

A: you're a beginner,
B: the data is very simple and user specific,
C: prototyping a frontend app and want to save time

Use an SQL if

A: your data will have a multiple relationships,
B: You have strong confidence of the data's schema going in.

I'm lost

If you've gotten this far and still don't know what I'm talking about, then just choose a Document DB. A lot of my beginner projects was built with CouchDB. It's easy to understand and fast to set up and update.

Like most people, I created a note taking app. This was perfect for a Document DB.

flowchart TB

%% Hardware
noteIds("notesId []")
userId("userId")


subgraph Your DB

	subgraph "User 👨‍🦲"
		id
		name
		email
		password
		noteIds
	end
	
	subgraph "Note 📝"
		id
		title
		list
		userId <--> noteIds
	end
	
end

You can see I 'link' the data points of User and Note with a noteIds and userId.

I use 'link' in quotes because when I query the User data, I'm only receiving an array of note ids, then I have to make another query to the notes and find the related ids. As your db grows sooner or later you'll hit this wall of creating these manual links between data.

developer_box📦