xDB

A DBMS implemented for Xidian University‘s compiler course.

Build

Ubuntu 22.04

To get the third party dependencies(via source code), run:

git submodule init
git submodule update

Install the following libraries on your computer

# required by rocksdb
sudo apt-get install libgflags-dev libzstd-dev libsnappy-dev zlib1g-dev libbz2-dev liblz4-dev
# required by protobuf
sudo apt-get install libprotobuf-dev protobuf-compiler

Features

• Expression evaluation(Nested)
• SQL comment
• NOT NULL column constraint
• Datatype: INT, FLOAT, CHAR(N)
• Multi-line support
• sql file execution
• Line editing and sql history
• Select multiple tables
• Based on persistent key-value storage(built upon LSM-Tree)

Supported SQL (Example)

CREATE DATABASE example;
USE example;
CREATE TABLE user (id int);
SHOW TABLES;
INSERT INTO user (id NOT NULL) VALUES (1);
SELECT id from user WHERE id = 42;
UPDATE user SET id=1 WHERE id=42;
DELETE FROM user WHERE id=42;
SELECT * from user where id=(1+2*2+(id=id)+id^id+id) AND id = id%2 AND id IS NOT NULL;
select * from t1  where id is not null;
DROP TABLE user;

More details in test.sql:

use test;
select * from test.table1,table1;-- duplicated table (It is correctly checked)

Build

mkdir build
cd build
cmake ..
make -j4

Project Structure

File	Description
include/*	all the header files
sql/*	intermediate representation(IR) for SQL
executor/*	execute SQL IR
executor/processor/*	processor for SQL expression(visitor pattern)
parser/sql.l	lexical analysis for SQL(flex)
parser/sql.y	syntax analysis for SQL(bison)
third_party/*	third party dependencies, e.g., googletest, rocksdb
test/*	unit test
docs/*	documentation for the project

Run

Start xDB interactive shell (interactive mode)

# Assuming you are in build directory
./xDB

Resources

• sqllogictest
• HuaDB
• BusTub
• USTC Compiler Principles
• SQL Parser