1 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall James A. Senns Information Technology, 3 rd Edition Chapter 7 Enterprise Databases and Data Warehouses

2 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Objectives Identify the reasons organizations choose to share databases and the functions of a database management system. Explain the difference between relational and object-oriented databases and their uses in business. Describe the differences between schemas, views, and indexes.

3 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Objectives (Continued) Discuss the benefits of client/server computing. Differentiate between shared and distributed databases. Explain why enterprises establish data warehouses and how they differ from data marts and enterprise databases.

4 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Objectives (Continued) Distinguish between a database administrator and a system programmer. Discuss database administration procedures and concurrency procedures and explain why these are an essential part of a shared database system.

5 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall The Principles of Data Sharing Definition Database: A collection of data and information describing items of interest to an organization. Entity: A person, place, thing, event or condition about which data and information are collected. Enterprise Database: A collection of data designed to be shared by many users within an organization.

6 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall The Principles of Data Sharing Definition (Continued)

7 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall The Principles of Data Sharing Database Management Systems Database Management Systems (DBMS): A program that makes it possible for users to manage the data in a database in order to increase accessibility and productivity. The Functions of Database Management: –Integrating Databases –Reducing Redundancy –Sharing Information –Maintaining Integrity –Enabling Database Evolution

8 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall The Principles of Data Sharing Database Management Systems (Continued)

9 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Enterprise Data Model Enterprise Data Model/Entity Relationship: A graphical representation of the items (the entities) of interest about which data is captured and stored in the database.

10 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Enterprise Data Model (Continued)

11 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Schema Schema: The structure of a database. Schema for Relational Database –Relational Database: A database in which the data are structured in a table format consisting of rows and columns.

12 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Schema (Continued)

13 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Schema (Continued) Schema for Object-Oriented Database –Object-oriented Database: A database that stores data and information about objects. –Object: A component that contains data about itself and how it is to be processed. –Action/Method: An instruction that tells a database how to process an object to produce specific information.

14 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Schema (Continued)

15 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Views View: A subset of one or more databases, created either by extracting copies of records from a database or by merging copies of records from multiple databases.

16 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Views (Continued)

17 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Indexes Index: A data file that contains identifying information about each record and its location in storage. Record Key: In a database, a designated field used to distinguish one record from another.

18 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Enterprise Database Structures Indexes (Continued)

19 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Client/Server Computing Definition File Server: A computer containing files that are available to all users interconnected on a local area network. Client/Server Computing: A type of computing in which all data and information retrieval requests and responses pass over a network. Much of the processing is performed on the server and the results of the processing are transmitted to the client.

20 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Client/Server Computing Definition (Continued)

21 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Client/Server Computing Definition

22 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Client/Server Computing Definition (Continued) Client: In client-server computing, a desktop workstation. Server: A computer that hosts a network and provides the resources that are shared on the network.

23 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Client/Server Computing The Benefits of Client/Server Computing

24 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Databases on the Internet Definition Web-based Integration: Makes data from enterprise databases available to users connecting through the Internet (including enterprise intranets and extranets).

25 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Databases on the Internet Definition (Continued)

26 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Distributed Databases Definition Shared Database: A database shared among many users and applications. Distributed Database: A database that resides in more than one system in a distributed network. Each component of the database can be retrieved from any node in the network.

27 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Distributed Databases Partitioning and Replication Partitioning: A method of database distribution in which different portions of the database reside at different nodes in the network. Replication: A method of database distribution in which one database contains data that are included in another database.

28 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Distributed Databases Distribution Strategies Geographic Distribution Strategy: A database distribution strategy in which the database is located in a region where the data and information are used most frequently. Functional Distribution Strategy: A database distribution strategy in which the database is distributed according to business functions.

29 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Distributed Databases Designed a Distributed Database Database Directory: The component of a shared database that keeps track of data and information. Other Design Factors –Storage Costs –Processing Costs –Communication Costs –Retrieval and Processing –Reliability –Frequency of Updates and Queries

30 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Distributed Databases Designed a Distributed Database (Continued)

31 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Data Warehouses and OLAP Definition Online Analytical Processing (OLAP): Database processing that selectively extracts data from different points of view. Data Warehouse: A large data store, designed from inquiries, that combines details of both current and historical operations, usually drawn from a number of sources.

32 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Data Warehouses and OLAP Comparison of Enterprise Databases and Data Warehouses

33 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Data Warehouses and OLAP Data Warehouse

34 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Data Warehouses and OLAP Definition Data Mining: Uses software designed to detect information hidden in the data. Data Marts: Processed to focus on a specific area of activities or isolated scientific or commercial processes.

35 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall People Definition Database Administrator (DBA): The IT professional responsible for managing all the activities and procedures related to an organizations database. Systems Programmer

36 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Procedures Database Administration Procedures Database Administration Procedures: The procedures associated with managing a database. –Database Planning –Database Design –Database Creation –Database Maintenance –Analysis of Usage –Creation and Monitoring of Security Procedures

37 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Procedures Concurrency Procedures Concurrent Data Sharing: A database procedure that allows several users to access the database simultaneously. Nonconcurrent Data Sharing: A database procedure that allows individuals to access a database only when no other person or application is processing the data.

38 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Procedures Concurrency Procedures (Continued) Record Locking: A concurrency procedure that prohibits another user from accessing or altering a records that is in use. File Locking: Used in systems that store unstructured information and have file-level sharing. Deadlock: A situation in which each user of a database is waiting for the others to unlock a record.