Query engines make me feel like a wizard. I cast my incantation: “Give me all the directors and the movies where Arnold Schwarzenegger was a cast member”. Then charges zip through wires, algorithms churn on CPUs, and voila, an answer bubbles up.

How do they work? In this essay, we will build a query engine from scratch and find out. In 100 lines of Javascript, we’ll supports joins, indexes, and find our answer for Arnold! Let’s get into it.

https://github.com/stopachka/datalogJS