---
title: SQL Architecture
description: The query engine layer and where it came from.
---

Dolt's SQL engine is built as a layer on top of its storage
engine. This allows us to implement non-SQL operations, such as the
CLI commands, directly against the storage layer. It also leaves the
door open to build additional database dialects on top of Dolt in the
future.

The SQL engine is implemented by three different open source projects,
listed below.

## vitess

[vitess](https://github.com/dolthub/vitess) is a MySQL sharding
management system. It implements the MySQL parser and the MySQL
server, including the wire protocol.

[Read more about the vitess project and how it's used in
Dolt.](/architecture/sql/vitess)

## go-mysql-server

[go-mysql-server](https://github.com/dolthub/go-mysql-server) is a
storage agnostic SQL query engine written in pure Go. It implements a
query analyzer and execution engine, and defines interfaces for
storage backend integrators (like Dolt) to implement.

[Read more about the go-mysql-server project and how it's used in
Dolt.](/architecture/sql/go-mysql-server)

## Dolt

The Dolt project itself implements the interfaces defined in
[go-mysql-server](https://github.com/dolthub/go-mysql-server) to make
the Dolt storage engine available for reads and writes in a SQL
context. It also implements many System variables and custom SQL
functions.

Dolt is responsible for the various interfaces to start, stop,
configure and manage SQL servers.