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Figure 6-6Microsoft 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.
Microsoft Access Data Dictionary Features
The Database Approach to Data Management
Some Drawbacks…• Complexity
• 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
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Continued..
• Cost of Conversion• 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 system4
Database Administrator • Oversees a staff of database specialists• Final recommendations for DB design• Load and maintain DB• Establish security controls• Perform backup and recovery
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Data Administration
Database Management
System
Data planning and modelling
technology
Database technology
And management
Data Administrator
Users
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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 7
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
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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.
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Skills of a Successful Systems Analyst
• Managerial• Ability to manage projects, resources, risk and change
• Interpersonal• Effective written and oral communication skills
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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.
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System UsersSystem 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 users12
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
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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.
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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.
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• 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
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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.
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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.
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Initiation
Analysis
Investigation
Implementation
Design
Maintenance
Traditional SDLC
NO FEEDBACK!!!!
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
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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 21
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
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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.
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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
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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
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Disadvantages of Prototyping• Better suited for smaller application development.
• Prototyping may mean glossing over essential steps in the system development.
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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
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Advantages of Software Packages
• Most of the design work has been completed in advance
• Little extensive testing required
• Vendor support and maintenance
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Disadvantages of Software Packages
• Disadvantages may be increased with a complex system
• Required customisation and additional programming may be expensive
• Hidden implementation costs
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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)
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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 31
Advantages to End User Development
• Improved requirements determination
• Increased user involvement and satisfaction
• Reduced application backlog
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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 data33
Definition - Outsourcing• The practice of contracting computer centre operations,
telecommunications networks, or application development to external vendors
• Example: Bank of Ireland, Dell
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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 35
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.36
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 revenue37
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
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