Database Design & Internals
Indexes, query planning, transactions and how databases are built.
Beginner
Start here. No background needed beyond school maths.
Database Normalization Description
A plain explanation of normalisation: why you split data into tables, the first three normal forms, and the trade-offs, with examples.
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DB-Engines Ranking
A monthly popularity ranking of database systems by type, handy for seeing which databases employers use and for comparing them.
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Advanced
Once the basics are comfortable.
Architecture of SQLite
A short tour of how a real database is put together: the tokenizer, parser, code generator, virtual machine, B-tree and pager.
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Let's Build a Simple Database
Build a small SQLite-style database in C, one step at a time: a REPL, a B-tree on disk, and how rows are stored and found.
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How Query Engines Work
A free book that builds a small query engine step by step, so you see how SQL becomes plans and results.
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Readings in Database Systems (the Red Book)
A curated reading list with commentary on the big ideas in database systems, from relational design to modern data stores.
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Expert
Research-level depth and specialist material.
CMU 15-721: Advanced Database Systems
Lecture notes, slides and recordings on modern database design: in-memory engines, query optimisation, vectorised execution and storage formats.
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The Internals of PostgreSQL
A detailed book-length guide to how PostgreSQL works inside: process and memory layout, query processing, transactions, the buffer manager and replication.
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