Sumit Kumar - Projects

SQLite's .db file is a single, self-contained binary format — no server, no separate WAL by default, just pages on disk. This project works through CodeCrafters' "Build Your Own SQLite" challenge, building a barebones SQLite reader in Go that can parse that format directly and answer basic SELECT queries against it, staged incrementally rather than all at once.

Each stage forces a deeper layer of the format: parsing the database header and page structure first, then reading table b-trees to list tables and their schemas, then walking b-tree leaf pages to actually read rows, and eventually using an index b-tree to do an index scan instead of a full table scan. It's the same progression this excellent explainer on SQLite's b-trees walks through — except here it has to actually run against real .db files, including a companies database with an index (idx_companies_country) that only pays off once the index-scan stage is implemented correctly.

Testing happens against real sample databases (sample.db with apples/oranges tables, superheroes.db for the table-scan stage, companies.db for the index-scan stage), so there's no faking it with synthetic data — the parser either reads the actual file format correctly or it doesn't.