Centralized Scheme Name Server Structure: name server assigns all names each site maintains a record of local data items sites ask name server to locate non-local data items Advantages: satisfies naming criteria 1-3 Disadvantages: does not satisfy naming criterion 4 name server is a potential performance bottleneck name server is a single point of failure Database System Concepts-6th Edition 19.14 ©Silberschat乜，Korth and SudarshanDatabase System Concepts - 6 19.14 ©Silberschatz, Korth and Sudarshan th Edition Centralized Scheme - Name Server Structure: name server assigns all names each site maintains a record of local data items sites ask name server to locate non-local data items Advantages: satisfies naming criteria 1-3 Disadvantages: does not satisfy naming criterion 4 name server is a potential performance bottleneck name server is a single point of failure