Introduction to Databases

Context

Remember when we implemented a global view-count counter with SSR? We had a server that kept some state in a random views.txt file so that even if the server or computer restarted, the total view count would not be reset.

When the data you're storing goes from a simple number to far more data (e.g., thousands of users and millions of posts), a simple .txt file is not enough for various reasons:

• Speed: Reading and finding specific data in one huge .txt file is slow (imagine finding a user's "score" if there's a list of a million users).
• Reliability: If someone deletes the text file, or if even one byte is corrupted, all your data may be gone!
• ACID: Atomicity, Consistency, Isolation & Durability. If you've taken a databases course, you will appreciate this more, but essentially it allows the database to behave well when there are many servers all making requests to it.

So what do we use instead of a .txt file? There are many options, but we will cover MySQL and MongoDB.