Let's Build a Simple Database
Writing a sqlite clone from scratch in C
View on GitHub (pull requests welcome)
This project is no longer under active development. You can read more here. But if you'd like to keep learning how to make your own SQLite clone from scratch, or one of many other projects like Docker, Redis, Git or BitTorrent, try CodeCrafters.
- What format is data saved in? (in memory and on disk)
- When does it move from memory to disk?
- Why can there only be one primary key per table?
- How does rolling back a transaction work?
- How are indexes formatted?
- When and how does a full table scan happen?
- What format is a prepared statement saved in?
In short, how does a database work?
I’m building a clone of sqlite from scratch in C in order to understand, and I’m going to document my process as I go.
Table of Contents
- Part 1 - Introduction and Setting up the REPL
- Part 2 - World’s Simplest SQL Compiler and Virtual Machine
- Part 3 - An In-Memory, Append-Only, Single-Table Database
- Part 4 - Our First Tests (and Bugs)
- Part 5 - Persistence to Disk
- Part 6 - The Cursor Abstraction
- Part 7 - Introduction to the B-Tree
- Part 8 - B-Tree Leaf Node Format
- Part 9 - Binary Search and Duplicate Keys
- Part 10 - Splitting a Leaf Node
- Part 11 - Recursively Searching the B-Tree
- Part 12 - Scanning a Multi-Level B-Tree
- Part 13 - Updating Parent Node After a Split
- Part 14 - Splitting Internal Nodes
- Part 15 - Where to go next
“What I cannot create, I do not understand.” – Richard Feynman
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