- Assume that you are an employee of consultancy company that specializes in the analysis design, and implementing of database systems. A client has recently approached your company with a view to implementing a database system but they are not familiar with the development.
- Provide three examples of user views for a database systems for a car Insurance Company such as GIECO.
Examples of User views (External Schema)
Example 1
Get a Quote View:
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Enter ZIP code
Example 2
User info View
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Residential Address
Indicate whether you are a new or a current customer
Example 3
Vehicle Info View
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Make
Model
Body Style
Purchase date
Was the vehicle purchased are new or old
Indicate whether the vehicle is leased, or owned
Use of the vehicle
Mileage of the Vehicle
Current Location of the Vehicle
On what basis do you choose one of the main approaches for managing multiple user views?
There exist several schema approaches that can be sued for managing multiple user views. Three level schema, which comprises of three levels (namely; the physical level, the conceptual level and the external level), is one such approach that is most commonly used to manage multiple user views. It is worth noting that a database is an important asset of an organization whose utility and ability to serve an organization excellently is dependent on the ability of the organization to choose the best approach for the database system. For instance in an organization like a bank, where data needs to be shared with other branches, an approach to a database system should be one that allow extensive sharing of data without permitting duplication and inconsistency. This is because there are instances when data will be entered into the system from other branches. Additionally, the database approach should take into consideration the accessibility of the data especially by programmers. Other factors of consideration on choosing a database management system approach include; low maintenance, permit data interdependence and improve standards of system developers.
b) How do the contents of users requirements specification differ from a system’s specification? Also provide one example for each type requirement for the case describe in (a).
User requirements denote the end-user needs for a database. Ideally, user requirements refer to what the user of the systems wants the database should do. Systems requirement on the other refer to the specifications that the chosen approach should meet in order to satisfy the user needs, For instance, a user might want a database system able to validate social security numbers provided my clients during the process of applying for a vehicle insurance policy. This represents a user requirement, while what should be done to ensure that the system verifies the submitted social security numbers represents a systems requirement
- Assume that you are an employee of Consultancy Company that specializes in the analysis design, and implementing of database systems. A client has recently approached your company with a view to get answers to the questions listed below. Provide your answers in writing.
- Discuss on how you would identify entities from users' requirements specification.
There is a big difference between entities and user requirement specifications in database systems. Unlike user database specification requirements that stipulate what the database needs to be able to do, entities are the distinct thing or objects utile in the database systems development. For instance, a user requirement specification can be that they system should be able to provide viewers with model options that are relevant to the type of vehicle chosen by the viewer. In this case, for instance, when a viewer chooses Toyota as a vehicle, only Toyota models should be availed for the viewer to pick from. The vehicle models, therefore, become the entities in this case.
- Discuss the important role played by users at the stage of database design.
Users play an important role at the database design stage. It can be noted that system requirement specifications depend on user requirement specifications. However, user requirement specifications do not depend on system requirement specifications. It means that system requirement specifications cannot exist without the existence of user requirement specifications. Users play the important role of generating the user requirement specifications that are utile in database design.
- 3. Answer the questions for the two cases presented below. You may state any appropriate assumption.
- Identify the main entity types. Whenever appropriate determine super - classes and their subclasses for the case.
b) Identify the main relationship types.
Customer owns one vehicle
Customer owns more than one vehicle
Vehicle has only one owner
Full time Faculty member engages in one or more research projects
Part time faculty member participates in one or more research projects
A research project is done by one or more full time or part time faculty members
c) Determine the cardinalities and participations associated for each relationship type in (b).
- One customer Can own one or more vehicles
- However One vehicle cannot be owned by two customers
- A customer can own a minimum of one vehicle
The cardinality that emerges is a 1:*
- One Full time faculty member can engage in one or more research projects
- Similarly, one part time faculty member can engage in one or more research projects
- One research project can be done by one or more faculty member (full time or part time)
The cardinality that emerges is a *:* in both Full time faculty and part time faculty participations.
- List three attributes for each strong entity type identify one attribute of a relationship identify in (b).
- Vehicle is a weak entity
- A customer can own more than one vehicle
- A vehicle cannot exist without an owner.
- Research project is a weak entity
- Full time faculty and part time faculty are strong entities
- Research project cannot exist without participants
- Draw the Entity Relationship Diagram (ERD) or Enhanced (EERD) using the UML notation.
- Explain the conceptual data model presented in Figure 1 to end users in plain English using no more than three paragraphs. In your answer be as specific as possible by explaining the entity types and relationship types represented as well as the cardinalities and participations associated with each relationship type.
In the ERD diagram, a bank has customers who can be a secretary, and engineer, or a technician. During registration, a secretary needs to indicate his or her typing speed while and an engineer has to specify his or her certification number. A technician, on the other hand, needs to specify the area of specialty. Upon registration, customers are given customer ID are required to contact a bank branch together with the date of birth of the customer. Since the bank has several branches, each branch as a branch ID, a name, and an address.
Existing relationship types are; a customer contacts a bank branch, and a bank branch contacts a customer. Major entities in the diagram are; Customer, and Bank. Secretary, Engineer, and technician are attributes. The participations here are that a customer a customer can contact one or more bank branches, while the bank branch can only contact a specific client bank which a response. In this regards, it can be noted that the 1..* cardinality implies than a one customer can contact a branch in a numbers of ways, while the 1..1 cardinality implies that a branch can only contact a customer in only one way.
