分布式数据库系统06工硕作业.ppt

分布式数据库系统06工硕作业 2007.02.03 csli整理 第一次作业 PPT4 关系数据库语言 Exercise Write the following queries, based on the following database example： Movie (title, year, length, inColor, studioName, producerC#) StarsIn (movieTitle, movieYear, strName) MovieStar (name, address, gender, birthdate) MovieExec (name, address, cert#, netWorth) Studio (name, address, presC#) In SQL. 1. Find Sandra Bullock’s birthdate 2. Find all executives worth at least $10,000,000 3. Find all the stars who either are male or live in Malibu 4.Which stars appeared in movies produced by MGM in 1995? 5. Who is the president of MGM studio? 第一次作业 1. Find Sandra Bullock’s birthdate select birthdate from MovieStar where name = “Sandra Bullock” 2. Find all executives worth at least $10,000,000 select name from MovieExec  where netWorth = 3. Find all the stars who either are male or live in Malibu  select name from MovieStar where address = “Malibu” or gender = “male” 4. Which stars appeared in movies produced by MGM in 1995? select strName from StarsIn where movie Title in (select title from Movie where studioName = “MGM” and year = “1995”) 5. Who is the president of MGM studio? Select presC# from Studio where name = “MGM” 第二次作业 PPT6 分布式数据库设计（教科书第三章） 已知有如下两种段分配: A R1在Site1, R2在Site2, R3在Site3. B R1和R2在Site1, R2和R3在Site3. 另已知有如下应用(所有应用的频率相同) A1: 在Site1上发出, 读5个 R1记录, 5个 R2记录 A2: 在Site3上发出, 读5个R3记录 , 5个R2记录 A3: 在Site2上发出, 读10个R2记录. 问: 1. 如果以本地应用为主要设计目标, 那个分配较优? 2. 假定A3改为要修改10个R2记录, 并仍以本地应用为其设计目标, 则那个分配方案较优? 第二次作业 解：首先完善模型如下： 假定：B方案中Site1上的R2和Site3上的R2是完全相同的，即冗余；本地读写的代价可忽略不计；所有异地读操作的单位记录代价均相等，记为1；所有异地写操作的单位记录代价均相等，记为1。 1 A方案 B方案 2 A方案 B方案 A1代价 5 0 5 0 A2代价 5 0 5 0 A3代价