Build Your Own Database A step-by-step guide to building a key-value database from scratch.
If you were to build your own database today, not knowing that databases exist already, how would you do it? In this post, we'll explore how to build a key-value database from the ground up.
A key-value database works more or less like objects in JavaScript—you can store values using a key and retrieve them later using that same key:
$ db set 'hello' 'world' $ db get 'hello' world
Let's find out how they work!
The Humble File Databases were made to solve one problem: Problem How do we store data persistently and then efficiently look it up later? The typical way to store any kind of data persistently in a computer is to use a file . When we want to store data, we add the key-value pair to the file: Add Reset $ db set 1 "Lorem ipsum" $ db set 18 "dolor sit" db.txt 001 : Lorem ipsum 001 : Lorem ipsum
018 : dolor sit 018 : dolor sit When we want to look for a specific key, we iterate through the pairs to see if there's a matching key: Search Reset $ db set 1 "Lorem ipsum" $ db set 18 "dolor sit" db.txt 001 : Lorem ipsum 001 : Lorem ipsum
018 : dolor sit 018 : dolor sit For updates, we'll find the key and replace the value in-place: Update Reset $ db set 1 "Lorem ipsum" $ db set 18 "dolor sit" db.txt 001 : Lorem ipsum 001 : Lorem ipsum
018 : dolor sit 018 : dolor sit And for deletes, we'll delete the record from the file: Delete Reset $ db set 1 "Lorem ipsum" $ db set 18 "dolor sit" db.txt 001 : Lorem ipsum 001 : Lorem ipsum
018 : dolor sit 018 : dolor sit Easy! We're done right? db.txt 001 : Lorem ipsum 001 : Lorem ipsum
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