Tài liệu Activity 5.1: Identifying Keys in the Logical Model pdf

Activity 5.1: Identifying Keys in the Logical Model In this activity, you will identify primary, foreign, and if necessary composite keys in the logical data model for Ferguson and Bard

Activity 5.1: Identifying Keys in the

Logical Model

In this activity, you will identify primary, foreign, and (if necessary) composite keys in the logical data model for Ferguson and Bardell, Inc

Objectives

After completing this activity, you will be able to:

! Identify primary, foreign, and composite keys in a logical data model

! Select a primary and foreign key type that is appropriate for a given entity

Before You Begin

This activity will be completed individually, with a class discussion to follow

Time to complete this activity: 20 minutes

22 Activity 5.1: Identifying Keys in the Logical Model

Exercise 1:

Identifying Keys

In this exercise, you will identify primary, foreign, and composite keys for a logical data model based on the Ferguson and Bardell, Inc case study

! Specify the keys in a logical data model

1 Review the ER diagram on the next page

2 Identify the areas of the ER diagram for which keys are necessary

3 Write the keys in the space provided on the ER diagram

4 Label each key as necessary, using the following syntax:

Primary Key: (PK) Foreign Key: (FK) Composite Key: (CK) Draw a line under the attributes used to define the composite key, and then label their types as Primary or Foreign

Next, you will discuss your answers with the class

Activity 5.1: Identifying Keys in the Logical Model 23

Name

Address

SSN

E-Mail

Type

Salary

BillableRate

Employee

EmployeeFirstName EmployeeLastName ClientName ClientLocation Date

Expenses TotalHours BillableHours Description

Timesheet

ClientName ClientAddress ClientCity ClientState ClientZip Date Amount Work Description Invoice

Name Address City State Zip

Client

Make

Model

VIN

Year

BeginMileage

EndMileage

MaintenanceCost1

MaintenanceDesc1

MaintenanceDate1

MaintenanceMiles1

MaintenanceCost2

MaintenanceDesc2

MaintenanceDate2

MaintenanceMiles2

MaintenanceCost3

MaintenanceDesc3

MaintenanceDate3

MaintenanceMiles3

Vehicle

Is Issued

Completes

Is Made From

Is Sent To Contracts With

JobDesc TaskDesc

Job Bills Time To

Client Employee StartDate EndDate Description Contract

Purchases

1

1 ∞

1

0 ∞

1

1 ∞

0 ∞

1 ∞

1

1 ∞

0 ∞

0 ∞

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