McGraw-Hill/Irwin Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter 13 Database Design for Student Loan Limited

13-2 Outline  Case description  Conceptual data modeling  Logical database design  Physical database design

13-3 Case Overview  Guaranteed Student Loans  Environment  Student  Lender  Service Provider  Guarantor  Department of Education  Replace existing information system

13-4 Loan Processing Workflow Apply Approve loan Originate loan Separate from school Send bill Make payment Miss payments Claim

13-5 Major Documents  Loan origination form  Disclosure letter  Statement of account  Loan activity report

13-6 Loan Origination Form

13-7 Loan Origination ERD

13-8 Disclosure Letter Structure

13-9 Disclosure Letter ERD

13-10 Statement Structure

13-11 Statement ERD

13-12 Loan Activity Structure

13-13 Loan Activity ERD

13-14 Schema Conversion Rules  Entity type rule  1-M relationship rule  M-N relationship rule  Identification dependency rule

13-15 Schema Conversion Result

13-16 Normalization  Student not in BCNF because of Zip FD  Zip  State  Loan not in BCNF because of RouteNo FD  RouteNo  DisBank  Institution not in BCNF because of Zip FDs  Zip  City, State

13-17 Normalized Table Design

13-18 Physical Database Design  Application profiles: tables, conditions, parameter values, and frequencies  Table profiles: estimated number of rows and distribution of values  Index selection: clustering and non clustering indexes  Derived data and denomalization  Other implementation considerations

13-19 Application Profiles

13-20 Application Frequencies

13-21 Table Profiles

13-22 Index Selections

13-23 Derived Data and Denormalization Decisions  Derived data  Loan.NoteValue  DiscLetter and LoanActivity tables have derived data in the image columns.  Denormalization  LenderNo and Lender.Name in the Loan table violates BCNF, but it may reduce joins between the Loan and the Lender tables

13-24 Other Implementation Issues  Processing volumes in a new system can be much larger than in the old system  Poor quality of old data may cause many rejections in the conversion process  Size of image data

13-25 Application Development Notes  Provides cross check on quality of database design  Data requirements for forms and reports  Loan origination form  Loan activity report  Derived data maintenance: AFTER ROW trigger for Loan.Balance

13-26 Summary  Case includes a significant subset of student loan processing.  Solution depicts models for database development phases.  Next step: database development for a real organization  Open-ended, unclear, and changing requirements are challenges.