1. INTRODUCTION TO INFORMATION SYSTEMS LECTURE 9: DATABASE FEATURES, FUNCTIONS AND ARCHITECTURES PART (2) أ/ غدير عاشور ashour.ghadeer@gmail.com 1

2. Data Resource Management  Organizations and their managers need to practice Managerial activity  Appling IS technologies like data management and data warehousing to manage data resources to meet the information needs of business stakeholders 2

3. Types of databases 3  Continuing developments in information technology and its business applications have resulted in the evolution of several major types of databases:  Operational databases  Distributed databases  External databases  Hypermedia databases

4. Types of databases 4

5. Operational Databases  Store detailed data to support business processes  Examples, customer database, inventory database  It is also called transaction database or production database  Example:  Human resource database that include data identifying each employee and his or her time worked, training and development status 5

6. Distributed Databases  Copies or parts of databases on servers at a variety of locations  Advantages :  Protection of valuable data from loosing in case of fire or damage to the media holding the data.  Large database may distribute into smaller databases based on some relationships between data Example: a huge company with several branches operations may distribute its data so that each branch has its own database while any other branches can access its database. 6

7. Distributed Databases 7  Challenge: any data change in one location must be made in all other locations. This change can be made in one of two ways:  Replication: Look at each distributed database and find changes Apply changes to each distributed database Very complex  Duplication Identify one database as a master Duplicate that database after hours in all locations Easier

8. External Databases  Databases available for a fee from commercial online services or from World Wide Web  Examples: when you use search engine like google or yahoo to look up something on the internet, you are using an external database. 8

9. Hypermedia Database  Website database  Consists of hyperlinked pages of multimedia (text, graphics, video clips, audio segments)  Usually websites that described by HTML code or XML labels use hypermedia database. 9

10. Data Warehouse  Data Warehouse(DW) is a database used for reporting. It stores data that has been extracted from the operational, external and other databases of an organization  Data has been cleaned, transformed and cataloged to be analyzed  Used by managers and professionals for  Data mining,  Online analytical processing  Business analysis  Market research  Decision support 10

11. Data Warehouse 11  A data warehouse maintains its functions in three layers: staging, integration and access.  The functions are in the DW to meet the users' reporting needs.  Staging is used to store raw data that can be used by developers (analysis and support).  The integration layer is used to integrate data and to have a level of abstraction from users.  The access layer is used to get data out for users.  Data mart (DM) is the access layer of the data warehouse (DW) environment that is used to get data out to the users. The DM is a subset of warehouse for specific use of department

12. Data Mining  Data mining is the process of extracting patterns from data. Where data in data warehouse are analyzed to reveal hidden patterns and trends  Data mining is seen as an increasingly important tool by modern business to transform data into business intelligence giving an informational advantage.  It is currently used in a wide range of profiling practices, such as marketing, surveillance, fraud detection, and scientific discovery.  Examples: Perform market-basket analysis to identify new products Find root causes of quality problems Prevent customer attrition and acquire new customer Cross sell to existing customers Profile customers with more accuracy 12

13. Traditional File Processing  For many years, data stored and organized in independent files  In this traditional file processing approach, each business application was designed to use one or more specialized data files containing only specific types of data records  Example: a bank’s checking account processing application was designed to access and update a data file containing specialized data records for the bank’s checking account customer. Similarly, the bank’s installment loan processing application needed to access and update a specialized data file containing data records about the bank’s installment loan customer 13

14. Problems of File Processing 14  Problems:  Data redundancy: independent data files included a lot of duplicated data that recorded and stored in several files. This caused problems when data is needed to be updated since it required developing each file separately.  Lack of data integration : accessing data from several independent files required writing a special program which is costly and time consuming for some organizations

15. Problems of File Processing 15  Data dependence: in file processing system, files, storage devices, and software are dependent on each other. Thus changes in the format and structure of data and records within a file require making the same change for all the programs that use that file  Lack of data integrity: in file processing system, end user can define some data elements such as customer address. This divergence can cause problems in the development of programs. Also, the integrity (i.e. accuracy and completeness) of the data was suspect because there was no control over their maintenance.

16. Traditional File Processing 16

17. Database Management Approach  Was conceived to solve the problems encountered with file processing approach  Consolidate data records, that held in separate files, into databases that can be accessed by different programs  Use a database management system (DBMS) which serves as interface between users and databases:  DBMS includes database management software that has three major functions: Create new database Maintain the quality of database help end users access data 17

18. Database Management Approach 18

19. Database Interrogation  End users use a DBMS by asking for information via a query or a report generator and they can receive an immediate response in the form of video or report  Query language – immediate responses to ad hoc data requests  SQL: (Structured Query Language) an international standard query language found in many DBMS packages It is the language structured to ask questions that the DBMS can retrieve to answer. 19

20. Database Interrogation 20 The basic form is SELECT....... FROM...... WHERE After SELECT you list the data fields you need After FROM you list the fields or tables from which the data must be retrieved After WHERE you specify conditions that limit the search Example: natural language: what students have the full mark? SQL: SELECT * FROM Students WHERE grade= 20;

21. Database Interrogation 21  Graphical Queries It is difficult sometimes to have a correct SQL queries so most end user database management packages offer GUI (Graphical User Interface) Point-and-click methods They are easier to use and are translated by the software into SQL  Natural Queries similar to conversational English  Report generator – quickly specify a report format for information you want printed in a report

22. Natural Language versus SQL 22

23. Graphical Query Source: Courtesy of Microsoft Corp. 23

24. Database Maintenance  Database of an organization need to be updated to reflect new business transactions such as a new sale  Done by transaction processing systems with support of DBMS 24

25. Application Development  DBMS packages play a major role in application development  Use DBMS software development tools to develop custom application programs  Example: you can use a DBMS to develop the data entry screen, forms, reports or Web pages of a business application that access to a company database to find and update specific data  Application software developers do not need to develop data using conventional programming. Instead they can include Data Manipulation Language (DML) (e.g. SQL) statements in their software to perform the development 25

26. ANY QUESTIONS 26  Refer to chapter 5 of the book for further reading  Second mid exam will be on week 12 Saturday 18/12/2010