分布式DBMS 研究生课《高级数据库系统技术》 Advantages: Improved performance -Efficiency -Extensibility(addition of new nodes) -Transparency of distribution ° Storage of data . Query execution -Autonomy of individual nodes Problems Complexity of design and implementation -Data consistency Safety Failure recovery 重庆邮电大学空间信息系统研究所
研究生课《高级数据库系统技术》 重庆邮电大学·空间信息系统研究所 16 分布式DBMS
Distributed data base Environments 研究生课《高级数据库系统技术》 Distributed database environments omogeneous Heterogeneous Autonomous Nonautonomous Systems Gateways Full DBMS functionality Partial-Multidatabase Federated Unfederated Loose integration Tight integration 17 重庆邮电大学空间信息系统研究所
研究生课《高级数据库系统技术》 重庆邮电大学·空间信息系统研究所 17 Distributed Database Environments
Homogeneous 研究生课《高级数据库系统技术》 Homogeneous The same DbMs is used at each node A Autonomous Each DBMS works independently, passing messages back and forth to share data updates B Nonautonomous A central or master dBms coordinates database access and update across the nodes 重庆邮电大学空间信息系统研究所
研究生课《高级数据库系统技术》 重庆邮电大学·空间信息系统研究所 18 Homogeneous
Homogeneous Distributed Database 研究生课《高级数据库系统技术》 Environment Global User Global User Global Distributed Schema DBMS n DBMS DBMS DBMS DBMS Software Software Software Software 重庆邮电大学空间信息系统研究所
研究生课《高级数据库系统技术》 重庆邮电大学·空间信息系统研究所 19 Homogeneous Distributed Database Environment
Heterogeneous 研究生课《高级数据库系统技术》 ll Heterogeneous Potentially different DBMSs are used at each node A Systems Supports some or all of the functionality of one logical database 1. Full DBMS Functionality Supports all of the functionality of a distributed database 2. Partial-Multidatabase Supports some features of a distributed database aFederated Supports local databases for unique data requests Loose Integration Many schemas exist, for each local database, and each local dBms must communicate with all local schemas ii. Tight Integration One global schema exists that defines all the data across all local databases b Unfederated Requires all access to go through a central coordinating module. B Gateways simple paths are created to other databases, without the benefits of one logical database 重庆邮电大学空间信息系统研究所
研究生课《高级数据库系统技术》 重庆邮电大学·空间信息系统研究所 20 Heterogeneous