In a computer program, the database is the heart of handling data and provides a fast and efficient way of storing and retrieving data. Learning the database's internal architecture and looking into a fully featured database at the code level is not so easy because of the database's complexity. But SQLite is a nice little compact database that is used in millions of devices and operating systems. An interesting fact about the SQLite database is that its code base is highly readable. Most of the code is well commented, and the overall software architecture is highly layered. My previous article describes the backend implementation of the SQLite Database, while this article looks into how the SQLite compiler and the VM work at a high level.
As I mentioned earlier, SQLite has a highly layered architecture that can be separated into seven layers. We will go through each of the layers one-by-one.