Please provide a short (approximately 100 word) summary of the following web Content, written in the voice of the original author. If there is anything controversial please highlight the controversy. If there is something surprising, unique, or clever, please highlight that as well. Content:
Title: Build Your Own Database from Scratch
Site: build-your-own.org

 Introduction 
 Databases are not black boxes. Understand them by building your own
from scratch! 
 This book contains a walk-through of a minimal persistent database
implementation. The implementation is incremental. We start with a
B-Tree, then add a new concept with each chapter, and eventually go from
a simple KV to a mini relational DB. 
 Although the book is short and the implementation is minimal, it aims
to cover three important topics: 
 
 Persistence.  How not to lose or corrupt your data.
Recovering from a crash. 
 Indexing.  Efficiently querying and manipulating
your data. (B-tree). 
 Concurrency.  How to handle multiple (large number
of) clients. And transactions. 
 
 Contents 
 Part I: Simple KV Store
(Completed) 
 
 Introduction 
 Files vs Databases 
 Indexing 
 B-Tree: The Ideas 
 B-Tree: The Practice (Part
I) 
 B-Tree: The Practice (Part
II) 
 Persist to Disk 
 Free List: Reusing Pages 
 
 Part II: Mini
Relational DB (Work in Progress) 
 
 Rows and Columns 
 Range Query 
 Secondary Index 
 Transactions 
 Concurrent Readers and Writers 
 Query Language 
 
 Work in Progress… 
 Subscribe to be notified of new chapters and print releases.  
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 [🙂 Pre-Order] 
 
 
    See also:
     
 codecrafters.io 
    offers “Build Your Own X” courses in many programming languages.
     
    Including Redis, Git, SQLite, Docker, and more.
    
   
 Check it out