Dazzling Costumes Information System

Questions: Task 1 Draw a context diagram data flow diagram for the system described above. The format should be similar to the context diagram in figure 5-13 of your textbook.Task 2 Draw the Level 0 DFD (Data Flow Diagram). All processes on this diagram should be functional primitives. The format should be similar to the context diagram in figure 5-16 of your textbook.Task 3 Draw an ERD (Entity Relationship Diagram) which represents the entities described in the case study, fully normalised to reflect all entities, relationships, cardinality and optionality. Ensure to follow the crows feet notation to indicate cardinality. The format should be similar to the figure 9-21 of your textbook.Task 4 Create a 3NF design for the system described in the case study. Provide the entity attribute list in 3rd normal form to support the ERD in Task 3. Make sure that all primary and foreign keys are identified properly. It is not necessary to provide the earlier normalisation forms (1NF and 2NF) as these will not be markedTask 5 Draw a class diagram for the system described in the case study. The format should be similar to the class diagram in figure 6-30 of your textbook. Make sure to include all relevant attributes and methods for each class.Task 6 The Manager of Dazzling Costumes is most interested in your work. She has no knowledge of Systems Analysis and Design and has asked for a brief explanation of what you have done and what these mean to her. Write - 1 page report explaining your work in Tasks 1 5.Task 7 Briefly describe various system changeover methods. Suggest a changeover method for the system described in the case study and provide specific reasons to support your choice. Answers: Task 1: Context Diagram Task 2: Level 0 DFD Task 3: ERD Task 4: 3NF Relations The list of attributes is, CUSTOMER (CustomerID, FirstName, LastName, DOB, Gender, Address) EMAIL (Email, CustomerID) ITEMS_HIRED (CustomerID, PieceItemID, HiredDate, DueDate, ReturnedDate) PIECE_ITEM (PieceItemID, ItemID, PurchaseDate, PurchaseCost, Size, Color, Status, SpclDetails) ITEM (ItemID, Name, Brand, GenDesc ) Task 5: Class Diagram Task 6 In any information system development process, there are more than one phases. System analysis and design is a phase in system development process. In the information system development process for Dazzling Costumes, the system analysis and design phase has provided following deliverables, Context diagram Level 0 DFD diagram ER diagram and 3NF database design. Class Diagram The context diagram is a functional system design diagram that gives a high level view of the system. The focus is on defining the boundaries and scope of the system and representing the same. So, the context diagram has been created for that purpose. Level 0 DFD diagram has extended the context diagram one step further towards detailed diagraming. The level 0 DFD shows the flow of data through the system and the system is represented as a set of processes. The main functional areas of the system are represented by the system. The storage of information has been shown using data stores D1 and D2. The diagram shows what data flows through which process, originates from which external entity and goes where in the system. ER diagram has been developed for the database design part. Every information system has an underlying database. The system records information about the customers, items and pieces of the items. So, the database will stores details about these entities. On the other hand there are certain relationships between different pair of these entities. Those are represented in the database also. Finally there is an attribute list of the logical relational database. The relations are in 3NF. The class diagram structures the information system. It will show how real world entities are getting manipulated in the information system. The classes, attributes of each class, the methods for each class, association between 2 classes etc. are represented graphically in the diagram. In this way, these deliverables are created. In system development process, a phase can consume and utilize the deliverables from previous phases. The next phase that is system development will use the deliverables from this phase. Task 7 After system development and testing, the newly developed system is implemented and it replaces the old system. The replacement of the old system by the new one is caller as system changeover process. There are four different types of system changeover methods. I. Direct cutover As soon as the newly developed system comes to the operational state, the old system is disposed and the new system starts working. This method of system changeover is called direct cutover method. The process is very inexpensive as at a time, only one information system runs there. But, there are a lot of risks in this method. The system can crash due to various reason, there may be more load than the system can handle, some bugs etc. in that case the there will be losses of data. II. Parallel method As the name suggests, in parallel method, the old system is used for some specific time even after full implementation of the new system. There are two information systems that runs at a time, parallel to each other. The method is very expensive. Because more resources are needed to run two information systems. But it lowers the risks of data loss, even if the new system is crashed for some issue, the old system will operate. When the new system proves itself to work efficiently in the working environment and producing similar deliverables like the old system, then the old system is retired. III. Phased Operation For big projects, there are a number of business processes and usually the whole system implementation is broken down into multiple phases. In each phase, the new system is implemented and made available to a part of the business. When it performs in an expected way, then that is integrated to the implementation of next phase and the process continues until the new system is made available to the whole business. The process has limited risks and is less expensive than parallel method. However, it is hard to implement, as there may be compatibility issues while working on new and old systems partially at a time. IV. Pilot Operation In some cases, a business have multiple sites or locations. A location is selected from those as a pilot site. The new information system is implemented to the pilot site at first. This is not phased implementation, rather it is complete implementation at a smaller location. When the system performs as per requirements, then it is implemented to the rest of the sites. This process also have lowered risks and reasonable expense. (Shelly Rosenblatt, 2011) It is suggested that Dazzling Costumes should use parallel method. In their case, the manual system and the newly implemented system will run in parallel for some time. The process will not be very expensive as only one information system will run in their case. But the risks of data loss will be low. References Shelly, G. Rosenblatt, H. J., 2011. Systems Analysis and Design., Cengage Learning.