This is Episode 12 of The Vibe Coder’s Guide to the Machine: computer science for a new generation.
The previous episode kept the same million records three ways, and each way was quick at one question and slow at another. A database keeps records too, so it runs into the same problem. The difference is that a database will show you, in two words, which way it plans to look before it starts. And when you ask it to make a question cheap, it agrees, and then charges you for that on every write afterwards.
Say your app keeps orders now, not products, and you asked the assistant to store them properly. It chose SQLite, a database that lives in a single file on disk. It made a table called orders, and each row holds one order: an id, a customer and a total. The code reads well, the first query returns the right number, and the reply ends with a cheerful summary. The table has no way of telling you what kind of question it is ready for. To find out, I filled one like it with a million made-up orders and asked it something an account page would ask: how much has customer c4242 spent?
