Week8

Bordoloi, B & Lee,M 1994, ‘AN OBJECT-ORIENTED VIEW Productivity Comparison with Structured Development’, Information Systems Management, Vol 11, No. 1, pp.22 – 30

Bordoloi & Lee have given a very good comparison between structured and object-oriented systems development approaches. They first describe the basics about both the systems and then give a comprehensive comparison. They identify the areas where structured/objec-oriented approaches should be preferred.

Sinason, D.H & Normand, C.J 2006,’Omni Furniture Company: A Systems Development Life Cycle Case’, Journal of Information Systems, Vol.20, No. 2, pg. 81(ABI/INFORM Global)

 

Sinason and Normand have described the main steps that make up the system development life cycle. These include Systems analysis, systems design, systems implementation and system maintenance and support.

 

Laudon, K & Laudon, J 2006, Managing information systems: Managing the digital firm, 9^th Edn, Pearson education Inc.,Upper Saddle River, New Jersey.

This book has been very helpful as it takes you through the various phases of system development life cycle for both structured and object-oriented system development methods. It differentiates the methodologies in their working and design phases.

 

Valacich, J. S., George, J.F., Hoffer, J.A. 2001, Essentials of Systems Analysis & design, 1^st Edn, Prentice Hall, Upper Saddle River, New Jersey.

 

According to Valacich, George and Hoffer, a DFD is a common form of process model that shows a graphic that demonstrates the movement of data between external entities and the processes and data stores within a system, [2001]. In this book, Valacich, George and Hoffer have differentiated between classes, subclasses and super classes.

 

 

 

 

 

 

Week10

There are four types of Maintenance tasks.

1. Corrective Maintenance;

2. Adaptive Maintenance;

3. Perfective Maintenance;

4. Preventive Maintenance;

Corrective Maintenance

In corrective maintenance, the user submits a systems request that is evaluated, prioritized and evaluated. The system is maintained by diagnosing the problem and taking corrective measures accordingly. An example of such maintenance task required by SBP can be when a sales representative is having problems storing the data of a customer correctly.

Adaptive Maintenance

In adaptive maintenance , the system is made easier to work on by adding some enhancements to it. Adaptive maintenance can be sometimes even more difficult than new systems development as those added enhancements should work within the constraints of the existing system. Adding  some features of the yellow pages would make it easier for SBP Sales staff to correctly write down and correlate the information about a customer, his address, his phone number.

Perfective Maintenance

Perfective maintenance involves changing an operational system to make it more efficient, reliable and maintainable. This involves software re-engineering. At SBP, this type of maintenance is required when a new operating system is introduced by e.g, microsoft or any other leading operating systems vendors, to make the processes more efficient.

Preventive Maintenance

This requires analysis of areas where trouble is likely to occur. Such maintenance task is initiated by the IT department. This usually results in user satisfaction, decreased downtime, and reduced TCO.

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week12

What was the most difficult assessment item you completed in COIS20025 this term (not counting the examination which is not until the examination period)?

In my point of view, the most difficult part of the subject was when we had to find the differences between traditional and object-oriented systems development approaches.

What was difficult about it and how would you suggest it could be improved? 

The most difficult thing about it was that there were not many journals describing the clear differences. The fact that only a very little part of the topic was discussed in the lectures, that too didn’t describe the differences. There should be some mention of this topic in the lectures.

Name three (3) things you learnt this term in COIS20025.

The three things I’ve learnt from this subject are data modeling techniques as ERDs and process modeling techniques such as creating DFDs.  The different methods of changing over to the new system is another thing that I’ve learnt during this subject. To name the few, direct cutover, parallel, pilot and phased approaches are followed to change to the new system from an old one.

What career are you working towards?

I would be looking for a job as a junior systems analyst in the near future.

How will you be able to use the knowledge and skills learnt in this course in your future career?

In order to remain competitive in this global market place, organizations need to make their business processes more efficient. Information systems development can help organizations achieve that. This knowledge that I’ve gained in my first semester would provide me with the basic knowledge of the steps involved in development an efficient information system for any organization.

Week9

There are four methods for changing over from one information system to another

1. Direct cutover Method
2. Parallel Method
3. Pilot Method
4. Phased Method

Direct cut-over

In a direct cut-over change strategy, the old system is replaced by the new systems immediately.

This type of changeover is not advisable for SBP because it requires a lot of training for the employees to get used to the new system. One can also argue that a direct cut-over, if done correctly, is also likely to be the cheapest in terms of minimising duplication.

Parallel Operation

In this approach, both the old and the new system are run together at the same time. It is not advisable for SBP to follow this type of changeover approach as it will be the most expensive alternative as running the two systems in parallel would increase the running cost. Apart from being an expensive alternative, it allows a quick return to the old system if something goes wrong with the new system.

Pilot

In this approach, the new system is used in one part of the organization as a trial. SBP is a small organization, therefore, it does not have so many departments and locations to cater for this type of changeover approach.

Phased

Parts of the new system are introduced in the organization over time. Each module is checked, tested and trained upon by the users so that they become more comfortable in using that module before moving on to the new system. This also helps the developer in understanding the actual needs of the users and requirements of the system.

In SBP, taking the customer information can be automated first according to the new system in order to check if the system can cater for the needs of the employees responsible for taking the orders and saving customer records.

Week7

Name one way that the traditional and object-oriented approaches to information systems development are similar. Explain how they are similar.

Both of the approaches are similar in their systems development life cycle (SDLC). SDLC for both of them have 3 main steps. Analysis, Design and Implementation. Other steps include maintenance, services and training.

Name one way that the traditional and object-oriented approaches to information systems development are different. Explain how they are different.One of the basic differences in between them is that structured approach relies on top-down process decomposition, whereas, object oriented approach to systems development involves both top-down as well as bottom-up design regimes. In the analysis phase of O-O systems development where one needs to identify classes and objects, a top-down analysis is required. To reuse the code or classes from existing class libraries, a bottom-up approach is required

Week3

What is the traditional approach to systems development?

A traditional/structured system development approach, as mentioned before, chiefly focuses on modeling the processes. Processes include capturing, storing, manipulating, and distributing of data as it flows through the system, [Laudon & Laudon 2006]. Therefore these methods detach data from the processes/functions. According to Laudon & Laudon, a different programming procedure must be written every time an action needs to be taken on a particular part of data, [2006]. According to Bordoloi & Lee, data flow diagrams and entity relationship diagrams are used in structured methods as tools for process modeling and data modeling respectively, [1994].

A common form of process model for structured methods is a data flow diagram which  according to Valacich, George and Hoffer, is a common form of process model that shows a graphic that demonstrates the movement of data between external entities and the processes and data stores within a system, [2001]. A context level DFD describes the relationship between the system and the external entities whereas a lower level DFD describes the relationship between data stores and the processes that are carried out by the system. A lower level DFD explains process specifications using data dictionaries. Hoffer, Prescot and Mcfadden have described data dictionaries as repositories of information that document data elements of a database, [2005]. According to Laudon & Laudon, these data dictionaries not only contain information about individual parts of data and data groupings within the system but also define contents of data flow, [2006].

In structured analysis, process models like DFDs are converted in to structured charts which are top-down charts, showing all levels of process modules and the relationships between each of them, [Bordoloi & Lee 1994]. The data modeling is done by entity relationship diagrams which, normalized, can be translated in to relational database. Systems developed in such a way are normally referred to as traditional systems, [Bordoloi & Lee 1994].

What is the object-oriented approach to systems development?

In contrast, an object-oriented approach to systems development treats data and processes that work on that data, as “objects”. In other words, data and processes are encapsulated within an object, [Bordoloi & Lee, 1994]. In object-oriented approach, the procedures or processes are called methods, [Laudon & Laudon 2006]. Only methods associated with an object can access and modify the data encapsulated in the same object, [Laudon & Laudon 2006]. This is called the encapsulation. The information system is modeled as a collection of these objects and the relationships between them. Unlike structured approach, programs send a message for an object to perform an operation that is already embedded in it. Objects must collaborate between each other to make the system work, [Laudon & Laudon 2006].

In object-oriented analysis, there is a concept of class. As Hoffer, Prescot and McFadden describe, an object is an instance of a class that encapsulates data and process/methods, [2005]. According to Hoffer, Prescot and McFadden, a class is defined as an entity that has a definite role in the application domain about which the organization wishes to maintain state, behaviour and identity, [2005].

Bordoloi and lee are of the fact that in object-oriented development, the object model is built keeping in mind four basic elements, abstraction, encapsulation, modularity and hierarchy, [1994].  Abstraction occurs due to identification of similarities or common features between multiple classes or objects in the real world. This leads to generalization. Valacich, George & Hoffer have described that the classes which are generalized are called subclasses and the class they are generalized into is called a superclass, [2001]. Modularity refers to classes and objects packaged into modules in such way that makes their reuse convenient, [Bordoloi & Lee 1994].  According to Bordoloi and Lee, hierarchy can either be aggregation (a part of) or a generalization/specialization (a kind of) relationship, [1994]. When two classes have a kind of relationship, subclasses inherit the data and methods of their superclasses, and a subclass can augment or redefine the data and methods of its superclasses. This is explains the concept of inheritance, [Laudon & Laudon 2006].

In essence, object-oriented modeling starts with identification of objects and their classes in the problem domain, [Bordoloi & Lee 1994]. Object and class diagrams are made with class diagrams showing all the classes and their relationships and object diagrams showing all the objects and the messages that are being passed between them, [Bordoloi & Lee 1994]. The analysis stage changes in to design stage when low-level class objects are identifies with their attributes and methods. Similar objects are grouped into a class and classes are then grouped in to hierarchies in which subclasses inherit the attributes and methods of its superclass, [Laudont and Laudon 2006]. The implementation phase is carried out by converting the design into a program code using class library to identify re-usable design components, [Bordoloi & Lee 1994]. This leads to the creation of an object-oriented database, [Laudon & Laudon 2006].

Object-oriented systems can be viewed by using Unified Modeling Language which uses graphical diagrams. According to Booch, Rumbaugh & Jacobson, Unified Modeling Language or UML is a standard language for writing software blueprints. The UML may be used to visualize, specify, construct, and document the artifacts of a software intensive system. There are two principal types of diagrams are structural and behavioral diagrams, [Laudon & Laudon 2006]. Structural diagrams describe relationships between classes whereas object diagrams describe interactions in an object-oriented system, [Laudon & Laudon 2006].

What textbooks, journals and/or websites might be useful to search for articles about Comparing and contrasting the traditional and object-oriented approaches to systems development?

Bordoloi, B & Lee,M 1994, ‘AN OBJECT-ORIENTED VIEW Productivity Comparison with Structured Development’, Information Systems Management, Vol 11, No. 1, pp.22 – 30

 

Sinason, D.H & Normand, C.J 2006,’Omni Furniture Company: A Systems Development Life Cycle Case’, Journal of Information Systems, Vol.20, No. 2,  pg. 81(ABI/INFORM Global)

 

Laudon, K & Laudon, J 2006, Managing information systems: Managing the digital firm, 9^th Edn, Pearson education Inc.,Upper Saddle River, New Jersey.

 

Valacich, J. S., George, J.F., Hoffer, J.A. 2001, Essentials of Systems Analysis & design, 1^st Edn, Prentice Hall, Upper Saddle River, New Jersey.

 

Shelly, G.B, Cashman, T.J.& Rosenblatt, H.J 1998, Systems Analysis and Design, 3^rd Edn, Course Technology, 1 Main Street, Cambridge, MA 02142.

 

Hoffer, J A, Prescot, M B, McFadden, F R 2005, Modern Database Management. 7^th Edn, Pearson Education Inc, Upper Saddle River, New Jersey.

 

Booch, G, Rumbaugh, J & Jacobson, I 1998, The Unified Modeling Language User Guide, 1^st Edn, Addison Wesley, New York.

 

Nierstrasz, O 1989, Object-Oriented Concepts, Databases and Applications, 1st Edn, ACM Press and Addison-Wesley,.

 

Booch, G 2004, Object Oriented Analysis and Design with Applications, 3^rd Edn, The Benjamin/Cummings Publ. Comp., Redwood City.

 

Whitten, J.L 2001, Systems analysis and design methods, 5th Edn, Galgotia Publications New Delhi.

 

 

Week5

Process Name:     DVD Bank

Process Number: 2

Purpose              : The purpose of this process is to check if the requested dvd is available.

Input Data Flow: Request DVD

Output Data Flows: Availability Report, Request Rejection

Process Description:

This process checks whether the dvd requested by the customer is available in the store. It takes the requested DVD name as input and searches for it. If found, the process would create an availability report that goes further processing. If the dvd is not available, it would then generate a request rejection to the customer telling that the dvd requested is not available.

Notes:

The dvd name should be given in capital letters only.

Week4

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Week 2

Q1. What are the current problems with the Small Business Press subscriber list?

Answer

SBP has a very large customer base and subscriber list keeps on increasing as more and more users subscribe to the service. The problems SBP is facing are;

1. Updating the subscriber list is a problem as it is a very time consuming process and some of the staff are new to the organization which makes it even more difficult.

2. SBP cannot tell how many subscribers are there for a particular magazine.

3. SBP need to differentiate betweeen paying subscribers, potential subscibers & subscribers who receive a free copy.

4. SBP cannot predict the amount of revenue it would generate from subscriptions in the next 3 years from the paying subscibers as the list doesn’t differentiate between different subscriber types.

Q2. What information do you need to find out about the Small Business Press subscriber list to develop a detailed understanding of the current system?

Answer

I will be asking the following questions in order to understand the current system used to update or edit the SBP subscriber list.

How the subscriber list is managed?

On what basis you hand out the complementary magazines and determine a potential subscriber?

If the subscriber changes his details, what measures are taken to change the details in the subscriber list?

How is the amount of money that is generated from subscription, calculated at the moment?

How is the data feeded into the subscriber list at the moment?

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