Why SQL won

In this post we will be talking about databases and comparing popular SQL databases to popular NoSQL databases.

Let’s start with explaining what each option is a SQL database or RDBMS is a way to store data in rows and columns within a table. Here is an example users table:

ID	Username	Password
1	Admin	admin
2	User	user
3	Test	Test

Lets say each user has a pet. Here is the pets table:

ID	User ID	Pet
1	1	Cat
2	2	Dog
3	3	Dog

As you can see, the data is stored in tables and you would need to join the tables together to get the username, and pet in the same query. With this it would be easy to count all of the pets or count all of the users, it is also easy to count all users who have a pet or not. Some popular RDBMS are MySQL, PostgreSQL and SQLite. It is easy to find hosting for SQL databases because they are so common, they can be harder to scale when compared to NoSQL databases.

Now lets make the same data in a popular NoSQL database, MongoDB. MongoDB stores data in JSON-like documents without a structure, so the data types can change over time. Here is our example in MongoDB:

This would be the users collection:

{
    "_id": "1",
    "username": "Admin",
    "password": "admin"
}

Here is the pets collection:

{
    "_id": "1",
    "user_id": "1",
    "pet": "cat"
}

However it could also be one collection users:

{
    "_id": "1",
    "username": "Admin",
    "password": "admin",
    "pet": "cat"
}

As you can see both NoSQL and SQL databases are good options but because MongoDB does not force a structure on to your data, it can be harder to model your data and will change based on your program’s use case because of this it makes SQL easier to use and structure, when compared to MongoDB.

With all of that in mind I think RDBMS are going to stay as the best databases to use for most projects.

Thanks for reading.