Tài liệu Activity 5.2: Normalizing Data doc

Activity 5.2: Normalizing Data In this activity, you will normalize a set of entities from the Ferguson and Bardell, Inc. case study. Objectives After completing this activity, you will be able to: • Normalize a logical data design to third normal form. Before You Begin This activity is completed individually, with a class discussion to follow. Time to complete this activity: 30 minutes 26 Activity 5.2: Normalizing Data Exercise 1: Creating a Normalized Data Design In this exercise, you will evaluate a logical design and then redesign it based on your knowledge of keys and normalization to produce a fully normalized data design. ! Normalize the design to third normal form 1. Review the ER diagram on the next page. 2. Identify the areas of the ER diagram in which normalization rules are violated as follows: a. Data is duplicated within multiple entities. b. Attributes of an entity are not directly associated with that entity. c. Each entity does not have attributes that uniquely define each instance. 3. On the page opposite the ER diagram, sketch out your own ER diagram with normalization applied to the third normal form. Keep in mind that the data design shown on the next page is not optimized in any way. The keys provided may need to be redesigned as part of the normalization process. Next, you will discuss your answers with the class. Tip Activity 5.2: Normalizing Data 27 Name Address SSN E-Mail Type Salary BillableRate EmployeeID(PK) Employee ClientID(FK) EmployeeID(FK) JobID(FK) EmployeeFirstName EmployeeLastName ClientName ClientLocation Date Expenses TotalHours BillableHours Description TimesheetID(PK) Timesheet ClientID(FK) TimesheetID(FK) ClientName ClientAddress ClientCity ClientState ClientZip Date Amount Work Description InvoiceID(PK) Invoice Name Address City State Zip ClientID(PK) Client EmployeeID (FK) Make Model VIN Year BeginMileage EndMileage MaintenanceCost1 MaintenanceDesc1 MaintenanceDate1 MaintenanceMiles1 MaintenanceCost2 MaintenanceDesc2 MaintenanceDate2 MaintenanceMiles2 MaintenanceCost3 MaintenanceDesc3 MaintenanceDate3 MaintenanceMiles3 VehicleID(PK) Vehicle Is Issued Completes Is Sent To Contracts With JobDesc TaskDesc JobID(PK) Job Bills Time To ClientID(FK) EmployeeID(FK) StartDate EndDate Description ContractID(PK) Contract Purchases 1 1 ∞ ∞∞ ∞ 1 0 ∞ ∞∞ ∞ 1 1 ∞ ∞∞ ∞ 0 ∞ ∞∞ ∞ 1 1 1 ∞ ∞∞ ∞ 1 1 ∞ ∞∞ ∞ Is Made From 0 ∞ ∞∞ ∞ 0 ∞ ∞∞ ∞ THIS PAGE INTENTIONALLY LEFT BLANK . Time to complete this activity: 30 minutes 26 Activity 5. 2: Normalizing Data Exercise 1: Creating a Normalized Data Design In this exercise,. Activity 5. 2: Normalizing Data In this activity, you will normalize a set of entities from the