Part-II – Short Answer Questions [4 Questions – Each question carry 4 mark] 1.Wh
ID: 3689007 • Letter: P
Question
Part-II – Short Answer Questions
[4 Questions – Each question carry 4 mark]
1.What are the differences between the logical and physical ERDs? [4 points]
2.At the end of the design phase, there is a document named the system specification that describes the different design documents and their uses. What is the consolidated purpose of this deliverable and why is it important? [4 points]
3.What is referential integrity and how is it implemented in a relational database? [4 points]
4.Compare between the types of interface design prototypes. [4 points]
Part IV – Long Answer Questions
[4 Questions – 19 points]
A university has an online registration system that enables the staff of each academic department to examine the courses offered by their department, add and remove courses, and change the information about them (e.g., the maximum number of students permitted). It should permit students to examine currently available courses, add and drop courses to and from their schedules, and examine the courses for which they are enrolled. Department staff should be able to print a variety of reports about the courses and the students enrolled in them. The system should ensure that no student takes too many courses and that students who have any unpaid fees are not permitted to register. (Assume that a fees data store is maintained by the university’s financial office, which the registration system accesses but does not change).
1.Draw a level-0 data flow diagram (DFD) for the university registration system. [5 points]
2.Draw an Interface Structure Diagram (ISD) for the university registration system.[5 points]
3.Based on the data flow diagram created in section 1, create a structure chart for the system.
[5 points]
4.Develop a use scenario for the university registration system. [4 points]
Explanation / Answer
I am sure with part 1 any queries please comment
1)
Logical:
Logical ERD models information gathered from business requirements. Entities and relationships modeled in such ERD are defined around the business's need. The need of satisfying the database design is not considered yet.
Physical
>Physical ERD represents the actual design of database. It deals with conversion from logical design into a schema level design that will be transformed into relational database. When modeling a physical ERD, Logical ERD is treated as base, refinement occurs by defining primary keys, foreign keys and constraints. Sometimes, relationships need to be resolved by introducing additional tables, like a Linked table for a many to many relationship
2)
>The system specifications document contains the: physical process models, physical data model, architecture design, hardware and software specification, interface design and program design. These elements represent the blueprint for the physical system layout inclusive of server configurations, cable connectivity and any ancillary devices that will be a part of the overall system. Additionally, the documents contain software, hardware and technical specifications that will enable programmers and service personnel to operate the machinery as well as to prescribe the proper workaround, patches, fixes and software additions and upgrades to the physical system
>This is an important consolidation of documents because it provides the creator, end user and maintenance engineers with a written model of the system they are about to implement which will minimize errors as well as allow for timely and effective corrective measures
3)
Referential Integrity is set of constraints applied to foreign key which prevents entering a row in child table (where you have foreign key) for which you don't have any corresponding row in parent table i.e. entering NULL or invalid foreign keys. Referential Integrity prevents your table from having incorrect or incomplete relationship
Example
>If you have two tables Order and Customer where Customer is parent table with primary key customer_id and Order is child table with foreign key customer_id. Since as per business rules you can not have an Order without a Customer and this business rule can be implemented using referential integrity in SQL on relational databas
4)
Type of prototype Typical purpose General characterstics when to use
Concept prototype Analyze system High level,overall concept definition stage
Feasibility || determine feasibilty proof of concept for concept definition stage
Horiontal || Clarify scope and Demonstrates outer layer of Function Definition Stage
requirements human interface only
such as window,screens,menus
vertical || Refine database design, Demonstrates a working, Later portion of Function Definition Stage
test key components early though incomplete,
system for key functions
Functional Determine useable sequence demonstrate the typical Function Definition stage
Storyboarding for presenting information order in which information
is presented