1. Lecture IS3318
29/11/11

2. Intro to Databases File organization concepts
Computer system organizes data in a hierarchy
Field: Group of characters as word(s) or number
Record: Group of related fields
File: Group of records of same type
Database: Group of related files
Record: Describes an entity
Entity: Person, place, thing on which we store information
Attribute: Each characteristic, or quality, describing entity
E.g., Attributes Date or Grade belong to entity COURSE
This slide describes standard units of data be stored by a computer in an information system. (The smallest units common to all applications are bits and bytes – a bit stores a single binary digit, 0 or 1, and a byte stores a group of digits to represent a single character, number, or other symbol). This hierarchy is illustrated by the graphic on the next slide.
Ask students to come up with some other entities that might be found in a university database (Student, Professor, etc.)

3. The Data Hierarchy Figure 6-1
A computer system organizes data in a hierarchy that starts with the bit, which represents either a 0 or a 1. Bits can be grouped to form a byte to represent one character, number, or symbol. Bytes can be grouped to form a field, and related fields can be grouped to form a record. Related records can be collected to form a file, and related files can be organized into a database.
This graphic illustrates the hierarchy of data found in a database. It shows the student course file grouped with files on students’ personal histories and financial backgrounds to create a student database.
Figure 6-1

4. Data redundancy and inconsistency
Problems with the traditional file environment (files maintained separately by different departments)
Data redundancy and inconsistency
Data redundancy: Presence of duplicate data in multiple files
Data inconsistency: Same attribute has different values
Program-data dependence:
When changes in program requires changes to data accessed by program
Lack of flexibility
Poor security
Lack of data sharing and availability
This slide discusses the problems in data management that occur in a traditional file environment. In a traditional file environment, different functions in the business (accounting, finance, HR, etc.) maintained their own separate files and databases.
Ask students to describe further why data redundancy, inconsistency pose problems? What kinds of problems happen when data is redundant or inconsistence. Ask students to give an example of program-data dependence. What makes the traditional file environment inflexible?

5. Interfaces between application programs and physical data files
Database
Collection of data organized to serve many applications by centralizing data and controlling redundant data
Database management system
Interfaces between application programs and physical data files
Separates logical and physical views of data
Solves problems of traditional file environment
Controls redundancy
Eliminates inconsistency
Uncouples programs and data
Enables organization to central manage data and data security
This slide defines and describes databases and DBMS. Ask students to explain what the difference is between a database and a DBMS. What is the physical view of data? What is the logical view of data?

6. Human Resources Database with Multiple Views
This graphic illustrates what is meant by providing different logical views of data. The orange rectangles represent two different views in an HR database, one for reviewing employee benefits, the other for accessing payroll records. The students can think of the green cylinder as the physical view, which shows how the data are actually organized and stored on the physical media. The physical data do not change, but a DBMS can create many different logical views to suit different needs of users.
A single human resources database provides many different views of data, depending on the information requirements of the user. Illustrated here are two possible views, one of interest to a benefits specialist and one of interest to a member of the company’s payroll department.
Figure 6-3

7. Represent data as two-dimensional tables called relations or files
Relational DBMS
Represent data as two-dimensional tables called relations or files
Each table contains data on entity and attributes
Table: grid of columns and rows
Rows (tuples): Records for different entities
Fields (columns): Represents attribute for entity
Key field: Field used to uniquely identify each record
Primary key: Field in table used for key fields
Foreign key: Primary key used in second table as look-up field to identify records from original table
This slide introduces the most common type of DBMS in use with PCs, servers, and mainframes today, the relational database. Ask students why these DBMS are called relational. Ask students for examples of RDBMS software popular today and if they have every used any of this software. You can walk students through an example data base that you have prepared in Access or use one of the exercise data tables found at the end of the chapter. Identify rows, fields, and primary key.

8. Relational Database Tables
The graphic on this slide and the next illustrates two tables in a relational DBMS. Ask students what the entity on this slide and the next are.
The key field in the Supplier table is the Supplier number. What is the purpose of the key field?
A relational database organizes data in the form of two-dimensional tables. Illustrated here are tables for the entities SUPPLIER and PART showing how they represent each entity and its attributes. Supplier_Number is a primary key for the SUPPLIER table and a foreign key for the PART table.
Figure 6-4A

9. Relational Database Tables (cont.)
This slide shows the second part of the graphic on the previous slide. Notice that the foreign key in this table is the primary key in the Suppliers table. What is the purpose of the foreign key. Can multiple records have the same foreign key?
Figure 6-4B

10. Capabilities of Database Management Systems
Data definition capability: Specifies structure of database content, used to create tables and define characteristics of fields
Data dictionary: Automated or manual file storing definitions of data elements and their characteristics
Data manipulation language: Used to add, change, delete, retrieve data from database
Structured Query Language (SQL)
Microsoft Access user tools for generation SQL
Many DBMS have report generation capabilities for creating polished reports (Crystal Reports)
This slide discusses the three main capabilities of a DBMS, its data definition capability, the data dictionary, and a data manipulation language.
Ask students to describe what characteristics of data would be stored by a data dictionary. (Name, description, size, type, format, other properties of a field. For a large company a data dictionary might also store characteristics such as usage, ownership, authorization, security, users.)
Note that the data manipulation language is the tool that requests operations such as SELECT and JOIN to be performed on data.

11. Microsoft Access Data Dictionary Features
The Database Approach to Data Management
Microsoft Access Data Dictionary Features
Figure 6-6
This graphic shows the data dictionary capability of Microsoft access. For the field “Supplier Name” selected in the top pane, definitions can be configured in the General tab in the bottom pane. These General characteristics are Fields Size, Format, Input Mask, Caption, Default Value, Validation Rule, Validation Text, Required, Allow Zero Length, Indexed, Unicode Compression, IME mode, IME Sentence Mode, and Smart Tags.
Microsoft Access has a rudimentary data dictionary capability that displays information about the size, format, and other characteristics of each field in a database. Displayed here is the information maintained in the SUPPLIER table. The small key icon to the left of Supplier_Number indicates that it is a key field.

12. Some Drawbacks… Complexity Cost of DBMS
A DBMS is a complex piece of software all users must fully understand it to make use of its functionalities
Cost of DBMS
The cost varies significantly depending on the environment and the functionality provided. Must take into consideration recurrent annual maintenance costs

13. Continued.. Cost of Conversion Performance Higher Impact of Failure
Cost of converting existing applications to run on the new DBMS and hardware. (additional training costs)
Performance
DBMS is written for applications in general which means that some applications may run slower than before
Higher Impact of Failure
Centralization of resources increases vulnerability of the system

14. Database Administrator
Oversees a staff of database specialists
Final recommendations for DB design
Load and maintain DB
Establish security controls
Perform backup and recovery

15. Data Administration Data Administrator Database technology And
management
Database
Management
System
Data planning
and modelling
technology
Users
Information policies – rules governing the maintenance, distribution and use of information in an organization.

16. Systems Analyst
Or business analyst is a systems analyst that specializes in business problem analysis and technology-independent requirements analysis.
A programmer/analyst (or analyst/programmer) includes the responsibilities of both the computer programmer and the systems analyst.
Other synonyms for systems analyst include:
Systems consultant
Systems architect
Systems engineer
Information engineer
Systems integrator
Conversion Notes
We dropped “application analyst” and “information analyst” as variations described in the previous edition. It has become much less common.
Teaching Notes
Business analyst is becoming more popular because of the number of end-users and other knowledge workers being assigned to systems analysts roles in organizations.

17. Variations on the Systems Analysts Title
Other synonyms for systems analyst include:
Systems consultant
Systems architect
Systems engineer
Information engineer
Systems integrator
Conversion Notes
We dropped “application analyst” and “information analyst” as variations described in the previous edition. It has become much less common.
Teaching Notes
Business analyst is becoming more popular because of the number of end-users and other knowledge workers being assigned to systems analysts roles in organizations.

18. Role of the Systems Analyst
Study problems and needs of an organization
Determine best approach to improving organization through use of:
People
Methods
Information technology
Help system users and managers define their requirements for new or enhanced systems

19. Skills of a Successful Systems Analyst
Analytical
Understanding of organizations.
Problem solving skills
System thinking
Ability to see organizations and information systems as systems
Technical
Understanding of potential and limitations of technology.

20. Skills of a Successful Systems Analyst
Managerial
Ability to manage projects, resources, risk and change
Interpersonal
Effective written and oral communication skills

21. System Owners
System owners are the information system’s sponsors and chief advocates. They are usually responsible for funding the project to develop, operate, and maintain the information system.
No additional notes

22. System Users
System users are the people who use or are affected by the information system on a regular basis—capturing, validating, entering, responding to, storing, and exchanging data and information. A common synonym is client.
Types include:
Internal users
Clerical and service workers
Technical and professional staff
Supervisors, middle managers, and executive managers
Remote and mobile users (internal but disconnected)
External users
Teaching Tip
Update students on the trend of “telecommuting.” Telecommuting falls into our “Remote” users category.
Some students may confuse “remote users” and “external users.” The difference is that remote users work for the organization in question, while external users work for some other organization (or are direct consumers).
The growth of the Web is driving the increase in both remote and external users.

23. Stakeholders: Players in the Systems Game
A stakeholder is any person who has an interest in an existing or new information system. Stakeholders can be technical or nontechnical workers.
For information systems, the stakeholders can be classified as:
System owners
System users
Systems analysts
System designers
System builders
IT vendors and consultants
Conversion Notes
The classification scheme (system owners, system users, et al.) was moved up from Chapter 2 in the fourth edition.
Teaching Tips
You might want to remind students that a single individual can play multiple roles in a project. For example:
A person could be both a system owner and system user.
Many systems analysts are also system designers and builders.
It is sometimes useful to identify individuals who might play the various roles in a typical information system.

24. Systems Development Lifecycle (SDLC)
The systems development life cycle (SDLC) model is an approach to developing an information system or software product that is characterised by a linear sequence of steps that progress from start to finish without revisiting any previous step.
The SDLC model is one of the oldest systems development models and is still probably the most commonly used.

25. SDLC Traditional systems development lifecycle (Waterfall Model)
SDLC - very similar to a product life cycle in the consumer market because both a new product and information system develop through a number of stages.

26. The typical SDLC has the following steps:
Initiation
Feasibility study
System Investigation
System Analysis
Systems Design
Implementation
Review and Maintenance
These stages are frequently referred to as “conventional systems analysis”, “traditional systems analysis”, “the systems development life-cycle” or the Waterfall Model

27. SDLC or The Waterfall Model
The waterfall model describes a development method that is linear and sequential.
Once a phase of development is completed, the development proceeds to the next phase and there is no turning back.
The advantage of waterfall development is that it allows for departmentalisation and managerial control.
Imagine a waterfall on the cliff of a steep mountain. Once the water has flowed over the edge of the cliff and has begun its journey down the side of the mountain, it cannot turn back. It is the same with waterfall development.

28. The Waterfall Model Continued..
A schedule can be set with deadlines for each stage of development and a product can proceed through the development process and theoretically, be delivered on time.
Development moves from concept, through design, implementation, testing, installation, troubleshooting, and ends up at operation and maintenance.

29. Initiation
Traditional SDLC
Investigation
Analysis
Design
Implementation
NO FEEDBACK!!!!
Maintenance

30. SDLC
This is now regarded as the “hard” systems approach because of its rigid demarcation between phases.
It has shortfalls which lead to a number of difficulties
One major criticism of the model is that it doesn’t cater for revisiting previous phases to correct defects.
Feedback Loop – refinement of Waterfall Model

31. Potential Strengths of the Traditional SDLC
It has been well tried and tested
Use of documentation standards
Following the methodology should aid (At least to some extent) that roll out dates, budgets and expected benefits are met.
At the end of each phase, all parties involved in the project can review progress.
Much greater control on the development of computer applications and make possible the use of project management tools and techniques
Ensure that the specifications are complete and that they are communicated to the users, programmers etc

32. Potential Weaknesses of the Traditional SDLC
Criticisms of the methodology or perhaps of the way it was used include:
Failure to meet the needs of management
Unambitious systems design
Instability
Inflexibility
User dissatisfaction
Problems with documentation
Lack of control

33. Potential Weaknesses of the Traditional SDLC
Incomplete systems
Application backlog
Maintenance workload
Problems with the “ideal” approach
It does not allow for much reflection or revision.
Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.

34. Prototyping
Building an experimental system rapidly and inexpensively for end users to evaluate
It will be refined until it conforms to the users’ requirements
This is achieved through iterative development

35. Advantages of Prototyping
Useful when there is uncertainty about system requirements or systems design
Valuable for End-user interface design
Encourages end-user involvement throughout the systems development lifecycle

36. Disadvantages of Prototyping
Better suited for smaller application development.
Prototyping may mean glossing over essential steps in the system development.

37. Application Software Packages
A set of prewritten, precoded application software programs that are commercially available for sale or lease
Packages have increased as many applications are common to many businesses: payroll, accounts and inventory control

38. Advantages of Software Packages
Most of the design work has been completed in advance
Little extensive testing required
Vendor support and maintenance

39. Disadvantages of Software Packages
Disadvantages may be increased with a complex system
Required customisation and additional programming may be expensive
Hidden implementation costs

40. End User Development
The development of information systems by end users with little or no formal assistance from technical specialist
It has been made possible by fourth generation software tools (4GL)

41. Encouraging End User Development
The variety of application development tools available make it easier for end user development
Guidelines for managers to encourage intranet website development by end users:
Look for what makes sense
Spur creativity
Set some limits
Give managers responsibility
Make users comfortable

42. Advantages to End User Development
Improved requirements determination
Increased user involvement and satisfaction
Reduced application backlog

43. Risks of End User Development
It occurs outside the traditional mechanisms for information system management and control
Problems in ensuring that end-user developed applications meet organisations objectives and standards
Rapid systems development without a formal methodology may mean that testing and documentation is inadequate
Loose control of organisational data

44. Definition - Outsourcing
The practice of contracting computer centre operations, telecommunications networks, or application development to external vendors
Example: Bank of Ireland, Dell

45. Outsourcing
Outsourcing has become increasingly popular as companies believe that it is more cost effective than maintaining their own IS staff
Many companies are outsourcing software procurement and support to application service providers (ASPs) who provide and support business application and other software via the Internet and intranets to all of a company’s employees workstations

46. Benefits of Outsourcing
To reduce work in the information systems department.
When the IS function within an organisation is limited.
To improve the contribution of IT to enhance business performance.
To create new sources of revenue.

47. Benefits of Outsourcing
To reduce work in the information systems department
When the IS function within an organisation is limited
To improve the contribution of IT to enhance business performance
To create new sources of revenue

48. Risks associated with Outsourcing
May loose control over IS function
Heavy reliance on the vendor
Proprietary information may be leaked to the competition if sensitive data is available outside the organisation

49. Sample Questions
Discuss Porter’s Competitive Forces Model, considering the role of information systems in gaining competitive advantage. Illustrate your answer with diagrams and examples.
Outline and briefly explain the stages involved on the Systems
Development Lifecycle (SDLC).