xDB: A relational DBMS based on persistent key-value storage

GitHub link

xDB is a relational DBMS built upon persistent key-value storag written by Ruitian Zhong.

Features

• Expression(nested) evaluation (including +-*/%^, AND/OR, ... BETWEEN ... AND ..., IS NULL,IS NOT NULL on CHAR and INTEGER)
• SQL comment
• NOT NULL column constraint
• Supported Datatype: INT, FLOAT, CHAR(N)
• Multi-line support
• sql file execution(./xDB --filepath="/path/to/example.sql")
• Line editing and sql history
• Select multiple tables(a.k.a., Cartesian product)
• Based on persistent key-value storage(built upon LSM-Tree) like MyRocks and TiDB

More details in Supported SQL (Example).

Supported SQL (Example)

CREATE DATABASE example;
USE example;
CREATE TABLE user (id int,score float);
SHOW TABLES;
INSERT INTO user (id int 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;

Demo