{"slug": "building-a-sql-like-relational-database-engine-in-c-from-scratch", "title": "Building a SQL-like Relational Database Engine in C++ From Scratch", "summary": "The article describes Ark, a SQL-like relational database engine built entirely from scratch in C++ by developer Devansh Kashyap, with the goal of learning database internals rather than competing with production systems. The engine supports core SQL features including aggregate functions, filtering, joins, schema evolution via ALTER TABLE, and persistence, all implemented manually without external libraries or parser generators. The project is structured as a modular pipeline of tokenizer, parser, command objects, execution engine, storage layer, and persistence, with the source code available on GitHub for feedback.", "body_md": "Most of us use databases every day.\nBut at some point I started wondering:\nSELECT\nstatement?So instead of only reading about databases, I decided to build one.\nThat project became Ark — a SQL-like relational database engine written entirely from scratch in C++.\nI wanted to understand the internals of database systems by implementing the pieces myself instead of relying on existing engines or parser generators.\nThe goal wasn’t to compete with production databases.\nThe goal was to learn:\nArk currently supports:\nCOUNT\n, SUM\n, AVG\n, MIN\n, MAX\n)ALTER TABLE\nLIKE\npattern matchingORDER BY\nDISTINCT\nSAVE\n/ LOAD\n)Everything is manually implemented.\nNo external database libraries.\nNo parser generators.\nNo embedded SQL engines.\nThe execution pipeline looks roughly like this:\nQuery\n↓\nTokenizer\n↓\nParser\n↓\nCommand Objects\n↓\nExecution Engine\n↓\nStorage Layer\n↓\nPersistence\nThe project is split into modular components:\nCREATE TABLE employees (\nid INT,\nname STRING,\nsalary DOUBLE\n);\nINSERT INTO employees VALUES\n(1, \"Alice\", 95000.0),\n(2, \"Bob\", 72000.0);\nSELECT * FROM employees\nWHERE salary > 80000.0;\nOne of the most interesting challenges was implementing joins and schema evolution.\nHandling:\nALTER TABLE\nbecame much more complicated than I initially expected.\nParser correctness and diagnostics also took a surprising amount of effort.\nBuilding Ark taught me a lot about:\nIt also gave me a much deeper appreciation for real database engines.\nGitHub Repository:\nhttps://github.com/kashyap-devansh/Ark\nI’d genuinely appreciate feedback from people interested in:\nEspecially suggestions for improving the architecture or query engine.", "url": "https://wpnews.pro/news/building-a-sql-like-relational-database-engine-in-c-from-scratch", "canonical_source": "https://dev.to/kashyapdevansh/building-a-sql-like-relational-database-engine-in-c-from-scratch-42j4", "published_at": "2026-05-22 17:58:19+00:00", "updated_at": "2026-05-22 18:02:40.945085+00:00", "lang": "en", "topics": ["open-source", "developer-tools", "data"], "entities": ["Ark", "C++", "GitHub"], "alternates": {"html": "https://wpnews.pro/news/building-a-sql-like-relational-database-engine-in-c-from-scratch", "markdown": "https://wpnews.pro/news/building-a-sql-like-relational-database-engine-in-c-from-scratch.md", "text": "https://wpnews.pro/news/building-a-sql-like-relational-database-engine-in-c-from-scratch.txt", "jsonld": "https://wpnews.pro/news/building-a-sql-like-relational-database-engine-in-c-from-scratch.jsonld"}}