Activity 4 1 deriving entities and attributes from data requirements

Activity 4.1: Deriving Entities and Attributes from Data Requirements The process of identifying entities and attributes is the key to creating a logical data design.. This activity pro

Activity 4.1: Deriving Entities and

Attributes from Data Requirements

The process of identifying entities and attributes is the key to creating a logical data design This activity provides a real-world example of use case

requirements that you will analyze to identify entities and attributes

In each of the two exercises in this activity, you analyze a single aspect of a logical data design At the end of each exercise, the class will discuss the design you derived

Objectives

After completing this activity, you will be able to:

! Identify and derive data entities from use cases

! Identify attributes of the derived data entities

Before You Begin

This activity will take place in small groups with a class discussion following each exercise

To complete this activity, each group will need a flip chart and markers

Prerequisites

To complete this activity, you need the data requirements generated in the activities of Module 3

Time to complete this activity: 25 minutes

14 Activity 4.1: Deriving Entities and Attributes from Data Requirements

Exercise 1:

Identifying Data Entities

In this exercise, you will identify data entities from a set of use cases, data requirements, and scenarios

1 Refer to the data requirements generated in Activity 3.1

2 Review the following relationships If necessary, review the case study in the Appendix for additional information

• Consultants contract with particular clients; clients can have more than one consultant working for them

• Consultants complete timesheets for hours worked at a client’s site (billable hours) and hours spent on administrative tasks (nonbillable hours) (For purposes of this exercise, assume that each timesheet is for one client only.)

• Consultants must bill their time to an appropriate job and supply a valid task description, along with any expenses incurred that need to be billed back to the client

• Managers must approve completed timesheets

• Administrative assistants create invoices from the timesheets

• Invoices are sent to clients

• All consultants are assigned their own company vehicle

3 Identify all entities from the data requirements generated in Activity 3.1 and list them on the flip charts provided by the instructor

Entities: Employee, Invoice, Timesheet, Client, Contract, Job, Vehicle

Next, you will present your findings to the class

Activity 4.1: Deriving Entities and Attributes from Data Requirements 15

Exercise 2:

Identifying Entity Attributes

In this exercise, you will use the entities from Exercise 1 and the following additional information to determine which attributes of the entities need to be retained to identify the entity

Additional Information

! Invoices are created monthly

! Timesheets are submitted weekly

! The total salary expenditures for Ferguson and Bardell, Inc must be computable

! Timesheet information must be able to be summarized by clients and regions

! Consultants must track the following information on the vehicle they are issued: the mileage of the car when it was issued to them, the mileage of the car when it is returned to Ferguson and Bardell, Inc., the last three

maintenance items performed on the car, the cost of each repair, the date of the repair, and the mileage of the car at the time of the repair

1 Join the group to which you have been assigned by the instructor

2 Review the two entities from the previous activity assigned to your group by the instructor

3 For each entity, identify and list below at most five attributes of the entity that you need to track to fulfill the business requirements for this solution (If you identify more than five attributes for an entity, rank the attributes by priority and select the five attributes that are most important to track.)

Employee: Name, Address, SSN, E-mail, Type (consultant, manager, administrative assistant), Salary, Bill Rate

Invoice: Client, Amount, Date, Work Description Timesheet: Employee (first and last names), Date, Client, Billable Hours, Total Hours, Description

Client: Name, Address Contract: Client, Employee, Start Date, End Date, Description Job: Job Description, Task Description

Vehicle: Make, Model, Year, Vehicle Identification Number, Begin Mileage, End Mileage, Maintenance

16 Activity 4.1: Deriving Entities and Attributes from Data Requirements

4 Use the flip chart provided by the instructor to list the attributes for each of your assigned entities

Next, you will present your findings to the class.

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