1 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Chapter 9 Database Management Approaches

2 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Objectives u Describe distributed DBMSs u Discuss client/server systems u Define data warehouses and explain their structure and access u Discuss the general concepts of object-oriented DBMSs

3 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Objectives u Summarize the impact of Web access to databases u Provide a brief history of database management u Describe the network and hierarchical data models

4 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Distributed Databases u Computers at various sites u Connected with communications network u Distributed database is single logical database physically divided among networked computers u DDBMS supports and manipulates distributed databases

5 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Communications Network Figure 9.1

6 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Characteristics of Distributed DBMSs u Homogeneous l Same local DBMS at each site u Heterogeneous l At least two sites with different DBMSs

7 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Characteristics of Distributed DBMSs (con’t.) u Location transparency l User feels as though entire database is at their site u Replication transparency l User unaware of behind the scenes replication of the data u Fragmentation transparency l Logical object divided among various locations

8 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Advantages of Distributed Databases u Local control of data u Increased database capability u Added system availability u Added efficiency

9 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Disadvantages of Distributed Databases u Problems updating replicated data u More complex query processing u More complex treatment of concurrent update u More complex recovery measures u More difficult management of the data dictionary u More complex database design

10 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Rules for Distributed Databases u Local autonomy u No reliance on a central site u Continuous operation u Location transparency u Fragmentation transparency u Replication transparency

11 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Rules for Distributed Databases (con’t.) u Distributed query processing u Distributed transaction management u Hardware independence u Operating system independence u Network independence u DBMS independence

12 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Client/Server Systems Figure 9.4

13 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Two-Tier Client/Server Architecture Figure 9.5

14 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Three-Tier Client/Server Architecture Figure 9.6

15 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Advantages of Client/Server Systems u Lower network traffic u Improved processing distribution u Thinner clients u Greater processing transparency

16 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Advantages of Client/Server Systems (con’t.) u Increased network, hardware, and software transparency u Improved security u Decreased costs u Increased scalability

17 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Triggers and Stored Procedures u Triggers l Actions that occurs automatically in response to a particular database operation l Created by programmers l Use special SQL statements u Stored Procedures l Collection of SQL statements compiled and optimized by DBMS l Improves performance

18 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Data Warehouses u Subject-oriented, integrated, time-variant, nonvolatile collection of data in support of management’s decision-making process u Used for analysis of existing data u Resolves performance issues suffered by operational RDBMSs and OLTPs

19 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Data Warehouse Architecture Figure 9.7

20 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Data Warehouse Structure Figure 9.8

21 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski On-Line Analytical Processing u Optimized to work with data warehouses u Used to answer questions u Allows users to perceive data as a multidimensional data cube l Slice and dice l Drill down l Roll Up u Data mining

22 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Data Cube Representation Figure 9.9

23 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Slicing on Time Dimension Figure 9.11

24 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Dicing on Part Dimension Figure 9.12

25 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Rules for OLAP Systems u Multidimensional conceptual view u Transparency u Accessibility u Consistent reporting performance u Client/server architecture u Generic dimensionality

26 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Rules for OLAP Systems u Dynamic sparse matrix handling u Multiuser support u Unrestricted, cross-dimensional operations u Intuitive data manipulation u Flexible reporting u Unlimited dimensions and aggregation levels

27 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Object-Oriented DBMS (OODBMS) u System in which data and the methods operating on that data are encapsulated into objects u Store graphics, drawings, video, sound, and other complex objects called binary large objects (BLOBs) u General concepts l Objects and classes l Methods and messages l Inheritance

28 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Unified Modeling Language (UML) u Models various aspects of software development for OO systems u Includes several types of diagrams l Class l Use Case l State l Sequence l Activity l Collaboration l Component

29 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Class Diagram for Premiere Products Figure 9.19

30 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Class Diagram with Constraints Figure 9.20

31 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Class Diagram with a Generalization and a Constraint Figure 9.21

32 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Rules for OODBMSs u Complex objects u Object identity u Encapsulation u Information hiding u Types of classes u Inheritance u Late binding

33 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Rules for OODBMSs (con’t.) u Computational completeness u Extensibility u Persistence u Performance u Concurrent update support u Recovery support u Query facility

34 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Web Access to Databases Figure 9.22

35 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski History of Database Management u Early systems l GUAM, DL/I, IMS, IDS, IDMS u Relational products l DB2, Oracle, Sybase, Paradox, dBASE, Access, MySQL, SQL Server u OODBMSs l Gemstone, Objectivity/DB, Versant u ORDBMSs

36 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Network Data Model Figure 9.23

37 9 Concepts of Database Management, 4 th Edition, Pratt & Adamski Hierarchical Data Model Figure 9.24