从零实现一个数据库。

演示

1. 运行 FreedomServer 的main方法。
2. MySQL客户端需要5.7版本。终端中执行 mysql -hlocalhost -P8090 -upay -p123。
3. 执行sql。目前不支持建表语句。

   -- 查询
   SELECT p.title
   FROM papers p
   WHERE p.title LIKE 'selectivity';
   
   SELECT a.title, d.name
   FROM papers a, authors b, paperauths c, venues d
   WHERE b.name = 'E. F. Codd'
   AND c.authorid = b.id
   AND c.paperid = a.id
   AND a.venueid = d.id;
    
   SELECT a2.name, count(p.id)
   FROM papers p, authors a1, authors a2, paperauths pa1, paperauths pa2
   WHERE a1.name = 'Michael Stonebraker'
   AND pa1.authorid = a1.id 
   AND pa1.paperid = p.id 
   AND pa2.authorid = a2.id 
   AND pa1.paperid = pa2.paperid
   GROUP BY a2.name
   ORDER BY a2.name;
   
   -- 删除和新增
   delete FROM authors where id = 141801;
   select * from authors where id = 141801;
   insert into authors (id,name) values (141801, 'lty');
   select * from authors where id = 141801;
   
   -- 事务
   delete FROM authors where id = 141801;
   set transaction READ WRITE;
   insert into authors (id,name) values (141801, 'lty');
   select * from authors where id = 141801;
   ROLLBACK;
   select * from authors where id = 141801;
          
       

实现过程

1. 完成数据库作业cs186，也就实现了数据存储层和sql解析优化层，实现细节doc/cs186.org。代码在engine包中。
2. 加上mysql网络协议层，协议分析doc/protocol.md，协议层借鉴了Freedom。代码在server包中。