MiniSQL

Project Structure

• client - REPL client for connecting to the server
• server - MiniSQL server
• minisql - SQL AST interpreter
• parser - SQL parser
• proto - Implementation of subset of PostgreSQL protocol

Requirements

• Rust + Cargo with version >= 1.74.0 (using impl in return statements)
• Optional: psql cli for testing the server

Usage

Running the server

cargo run -p server -- [OPTIONS] --file <FILE>

Options:
  -a, --address <ADDRESS>  IP address for the server to listen on [default: 127.0.0.1]
  -p, --port <PORT>        Port for the server to listen on [default: 5432]
  -f, --file <FILE>        Path to the data file
  -h, --help               Print help

This will start the server listening on <ADDRESS>:<PORT> and load the state from <FILE>. If the <FILE> does not exist, it will be created.

Demo Database

A database with demo data is available in demo.json. To run the server with this database, use:

cargo run -p server -- --file demo.json

This database contains two tables:

• Table users with columns id, name, surname, email
• Table cars with columns id, vid, brand, model, year

Running the client

cargo run -p client -- [OPTIONS]

Options:
  -p, --port <PORT>          Port number of the server [default: 5432]
      --host <HOST>          Host name or IP address of the server [default: 127.0.0.1]
      --username <USERNAME>  User name [default: "minisql user"]
  -h, --help                 Print help

This will start a REPL client that connects to the server at <HOST>:<PORT> and authorizes with <USERNAME>. SQL queries can be entered line by line. The client will print the result of each query.

To exit the REPL client, enter exit or quit.

Features

• SQL must be on single line, in UPPERCASE and end with ;, as it should be
• Supported operations: CREATE TABLE, CREATE INDEX, SELECT, INSERT, DELETE
• Supported data types: UUID, STRING, INT, NUMBER
• Supported subset of PostgreSQL protocol, without authentication and simple query flow

Operations

CREATE TABLE

• Every table requires one column with type UUID as PRIMARY KEY

CREATE TABLE <TableName> (<ColumnName> <DataType>, ...);

With the demo database, this can be used to create a new table:

CREATE TABLE games (id UUID PRIMARY KEY, name STRING, year INT, price NUMBER);

CREATE INDEX

• Indexing is not supported for the NUMBER data type

CREATE INDEX <IndexName> ON <TableName> (<ColumnName>);

With the demo database, this can be used to create a new index:

CREATE INDEX CarsYear ON cars (year);

SELECT

• WHERE clause is optional and only equality is supported
• All columns can be selected with *

SELECT <ColumnName>, ... FROM <TableName> [WHERE <ColumnName> = <Value>];

With the demo database, this can be used to select all cars with year 2001:

SELECT * FROM cars WHERE year = 2001;

INSERT

INSERT INTO <TableName> (<ColumnName>, ...) VALUES (<Value>, ...);

With the demo database, this can be used to insert a new user:

INSERT INTO users (id, name, surname, email) VALUES (u12345, "John", "Doe", "johhny.trucker@seznam.cz");

DELETE

• WHERE clause is optional and only equality is supported

DELETE FROM <TableName> [WHERE <ColumnName> = <Value>];

With the demo database, this can be used to delete all users with name Christina:

DELETE FROM users WHERE name = "Christina";

Data Types

• UUID - special integer prefixed with u, e.g. u12345
• STRING - string enclosed in double quotes, e.g. "Hello World"
• INT - integer, e.g. 12345
• NUMBER - floating point number, e.g. 123.45

Testing with psql

Thanks to the subset of PostgreSQL protocol implemented in proto, the server can be tested with psql, which offers REPL client similar to the client crate:

psql -h <HOST> -p <PORT>