I built a SQL-like relational database engine in C++ from scratch

Hey r/cpp,

I’ve been learning systems programming and database internals, so I started building **Ark** — a SQL-like relational database engine written entirely from scratch in C++.

Current features include:

* Handwritten tokenizer ( lexer )
* Recursive descent parser
* CRUD operations
* INNER / LEFT / RIGHT / FULL joins
* Aggregate functions
* `ALTER TABLE` support
* File persistence
* Custom diagnostics system

Everything is implemented manually:

* no parser generators
* no embedded SQL engines
* no external dependencies

One of the most challenging parts so far has been handling joins, schema evolution, and persistence consistency cleanly.

GitHub:
[https://github.com/kashyap-devansh/Ark](https://github.com/kashyap-devansh/Ark)

I’d especially appreciate feedback around architecture, parser design, query execution, or persistence design.

https://redd.it/1tkrhxq
@r_cpp