Database Systems Introduction to Databases and Data Warehouses
Database Systems Introduction to Databases and Data Warehouses APPENDIX F – Distributed Databases, Parallel Databases, and Cloud Computing Copyright (c) 2016 Nenad Jukic and Prospect Press
DISTRIBUTED DATABASES § Distributed database system (DDBS) • Database system in which the database is distributed among separate computers Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
DISTRIBUTED DATABASES § Distribution transparency • Ensures that the end users can use the distributed database in the same fashion as if the database is not distributed Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
DISTRIBUTED DATABASES § Distributed database system (DDBS) - example Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
DISTRIBUTED DATABASES § Homogeneous DDBS, • All the computers run the same DBMS § Heterogeneous DDBS • Different DBMS can run on different computers Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
DISTRIBUTED DATABASES § Database fragmentation • Strategy for distributing the data across different locations in a distributed database o o o Horizontal fragmentation Vertical fragmentation Mixed fragmentation Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
DISTRIBUTED DATABASES § Horizontal fragmentation • Subsets of the records from a table stored at different locations Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
Horizontal fragmentation - Example Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
Horizontal fragmentation - Example Query: SELECT * FROM employee_location_a UNION SELECT * FROM employee_location_b; DDBS transparency allows this query to be issued as: SELECT * FROM employee Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide
DISTRIBUTED DATABASES § Vertical fragmentation • Subsets of the columns of a table are stored at different Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 10
Vertical fragmentation - Example Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 11
Vertical fragmentation - Example Query: SELECT FROM WHERE a. empid, a. empname, b. empgender, a. empphone, b. empbdate employee_location_a a, employee_location_b b a. empid = b. empid; DDBS transparency allows this query to be issued as: SELECT * FROM employee Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 12
DISTRIBUTED DATABASES § Mixed fragmentation • A combination of horizontal and vertical fragmentation Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 13
Mixed fragmentation - Example Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 14
Mixed fragmentation - Example Query: SELECT FROM WHERE UNION SELECT FROM WHERE a. empid, a. empname, c. empgender, a. empphone, c. empbdate employee_location_a a, employee_location_c c a. empid = c. empid b. empid, b. empname, c. empgender, b. empphone, c. empbdate employee_location_b b, employee_location_c c b. empid = c. empid; DDBS transparency allows this query to be issued as: SELECT * FROM employee Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 15
DISTRIBUTED DATABASES § Data replication • Storing more than one copy of the data at different locations in a distributed database • Fully replicated distributed database o The entire database replicated at each location in the distributed system • Partially replicated distributed database o Some parts of database replicated at multiple locations o Other parts are not replicated Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 16
DISTRIBUTED DATABASES § Federated database • A collection of preexisting databases that are connected into one system Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 17
PARALLEL DATABASES § Parallel databases • Uses multiple computers to work on the same task • Multiple computers perform the same operations simultaneously on different portions of the same data set Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 18
PARALLEL DATABASES § Massively parallel processing (MPP) • Uses a large number of separate computer processors running in parallel to execute a single program § Shared-nothing MPP architecture • A parallel system in which each processor has its own memory and disk storage Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 19
CLOUD COMPUTING § Cloud computing systems • Use the Internet to deliver data storage and processing services hosted by a service provider Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 20
CLOUD COMPUTING § Infrastructure as a service (Iaa. S) • Computer hardware provided as standardized services over the network § Platform as a Service (Paa. S) • Resources required for building applications provided as standardized services over a network § Software as a Service (Saa. S) • Computer applications offered as a service on demand § Database as a service (Daa. S) • Specialized version of Saa. S developed for database management in clouds Jukić, Vrbsky, Nestorov – Database Systems Copyright (c) 2016 Nenad Jukic and Prospect Press Appendix F – Slide 21
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