Chapter 13 Database Design for Student Loan Limited

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Outline Case description Conceptual data modeling Logical database design Physical database design

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Case Overview Guaranteed Student Loans Environment –Student –Lender –Service Provider –Guarantor –Department of Education Replace existing information system

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Loan Processing Workflow Apply Approve loan Originate loan Separate from school Send bill Make payment Miss payments Claim

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Major Documents Loan origination form Disclosure letter Statement of account Loan activity report

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Loan Origination Form

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Loan Origination ERD

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Disclosure Letter Structure

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Disclosure Letter ERD

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Statement Structure

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Statement ERD

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Loan Activity Structure

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Loan Activity ERD

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Schema Conversion Rules Entity type rule 1-M relationship rule M-N relationship rule Identification dependency rule

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Schema Conversion Result

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Normalized Table Design

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Application Profiles

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Application Frequencies

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Table Profiles

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Index Selections

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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.