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第五章 分布式数据库概述. 目录. 数据库系统发展 集中式系统 为什么需要分布式系统 分布式数据库体系结构的目标 并行与分布式数据库系统 分布式数据库的问题 分布数据独立与分布透明访问. 数据库系统发展. 基于数据模型 数据结构 , 操作 层次 , 网状 , 关系 , OO, 时态 , 空间 , 图 , 时空 , 文本 , 工程 , 生物 , 地理 , 图像数据库等 基于运行环境 集中式 , 分布式 , 并行 , Cluster, Web, 移动 , 嵌入 , 数据网格等数据库 主动 , 实时数据库等 事务处理. - PowerPoint PPT Presentation
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, , , , OO, , , , , , , , , , , , Cluster, Web, , , ,
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:PM..., ...
: . Site, , Site. Site, , . Site(LDB)DBMS, .
: London, New York .:EMP(ENO, NAME, TITLE, SALARY, ):
, E.g. , ,
, E.g. E.g. ,
EMPLondonPayroll appLondonNew YorkPayroll appNew YorkBei JingPayroll appBei Jing !
LondonEmpLondonPayroll appLondonNew YorkPayroll appNew YorkBei JingPayroll appBei JingBJEmpNYEmp!!
LondonPayroll appAnnual Bonus appLondonNew YorkPayroll appNew YorkBei JingPayroll appBei JingLondonEmpNYEmpBJEmp
LondonPayroll appAnnual Bonus appLondonNew YorkPayroll appNew YorkBei JingPayroll appBei JingLondonEmpNYEmpBJEmp,
LondonPayroll appAnnual Bonus appLondonNew YorkPayroll appNew YorkBei JingPayroll appBei JingLon, NYEmpNY, BJEmpBJ, LonEmp
RDBMSFilestape
(Homogeneous)SiteDB, (Heterogeneous)SiteDB. DDBSieSiteCopyDDB, SiteCopy(Site), Copy(Site)
, , :
(1) PPP...M
-(2) ......MM
-(3) ...
DDB LDDLDBGDDGDB
LDBMSDBCMDDDDBMS
111nnn..DDBMS
DBMSDBMSDBMS1234
DB!DBDB (, )
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: I/O:!
:LockingTimestamps
::
:Rain>1700mm,,. wine(year, name, producer, area, country) weather(year, area, country, sun, rain) winecountry, , . Weatherweather-R(year, area, country, rain) weather-S(year, area, country, sun).
-weather-R, , , , . = 3*18000+400+800+200 = 55400bytes wine-F, wine-I, wine-U , , . = 12000+15000+20000+1400 = 48400bytes
()DDBDB
, .: Supplier Supplier1 Supplier2 : Supplier1 Site1 Supplier2 Site2Site3(1) Read (Terminal, $S#)SELECT sname INTO $snameFROM SupplierWHERE s#=$S#;Write(Terminal, $sname);
(2) Read(Terminal, $S#);SELECT sname INTO $snameFROM Supplier1 WHERE s#=$S#;if not found THEN SELECT sname INTO $sname FROM Supplier2 WHERE s#=$S#;Write (Terminal, $sname);
(3) Read(Terminal, $S#);SELECT sname INTO $snameFROM Supplier1 AT Site1WHERE s#=$S#;if not found THEN SELECT sname INTO $sname FROM Supplier2 AT Site2WHERE s#=$S#;Write (Terminal, $sname);
(4) Read(Terminal, $S#);EXECUTE $SUPIMS($S#, $FOUND, $sname) AT Site1;IF not found THEN EXECUTE: $SUPCODASYL($S#, $FOUND, $sname) AT Site2;Write(Terminal, $sname);
2003
Ceri 1984 1992< > 1998 1999M. Tamer Ozsu and Patrick Valduriez, "Principles of Distributed Database Systems," Second Edition, Prentice Hall 1999.