CLASS DISCUSSION AND NOTES

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1 CLASS DISCUSSION AND NOTES February/March 2011 Mon Tue Wed Thu Fri Chap. 5 Data Modeling with ER Model 28 March Spring Break

2 I. GETTING STARTED COURSE OVERVIEW II. DATABASE DESIGN & IMPLEMENTATION III. SELECTED TOPICS Introduction (C-1) Introduction to Structured Query Language (C-2) Rel. Model and Normalization (C-3) Database Design and Normalization (C-4) Data Modeling with the ER Model (C-5) Transforming Data Models into Database Designs Managing Multiuser Databases (C-9) XML (C-13) SQL for Database Construction (C-7)

3 MODULE II: DATABASE DESIGN & IMPLEMENTATION Part 5: Data Modeling with the Entity- Relationship Model (Text: Chapter 5) NOTES FOR CLASS SESSION STARTING POINTS Questions to begin our deliberation 1. What are the major steps in designing databases that arise from the development of new information systems? 2. What is the purpose of a data model? Student Learning Objectives (Desired Outcomes) At the end of in-class and outside-class work on this topic, you should be able to: 1. Describe the two-phase data modeling/database design process. [Comprehension] 2. Discuss the purpose of the data modeling process. [Comprehension] 3. Describe entity-relationship (E-R) diagrams. [Comprehension]

4 4. Determine entities, attributes and relationships. [Analysis] 5. Create entity identifiers. [Synthesis] 6. Determine minimum and maximum cardinalities. [Analysis] 7. Describe and use ID-dependent and other weak entities. 8. Describe and use supertype/subtype entities. 9. Describe and use strong entity patterns. 10. Describe and use the ID-dependent association pattern. 11. Describe and use the ID-dependent multivalued attribute pattern. 12. Describe and use the ID-dependent archetype/instance pattern. 13. Describe and use the Line-Item pattern. [Comprehension/application] 14. Describe and use the For-Use-By pattern. 15. Describe and use the recursive patterns. 16. Discuss iterative nature of the data modeling process. [Comprehension] 17. Use the data modeling process. [Application]

5 QUESTIONS TO EXPLORE READINGS Q 1. What are the differences between systems analysis and design and database design? Q 2. Why should the database model fit the user requirements? Q 3. What the major strengths of the Entity Relationship Model? Q 4. Why is proper documentation of database design so important? In Class Exercise 5 Text Chapter 5: Data Modeling with the Entity-Relationship Model Points to consider (Please take time review all the points before starting the exercise): 1. A data model is a plan, or blueprint, for a database design. 2. A data model is more generalized and abstract than a database design 3. Entity Relationship model is a set of concepts and graphical symbols that can be used to create conceptual schemas 4. Entities Something that can be identified and the users want to track 5. Entity instance the occurrence of a particular entity

6 6. Attributes describe an entity s characteristics 7. Entities can be associated with one another in relationships 8. Cardinality means count, and is expressed as a number 9. Maximum cardinality is the maximum number of entity instances that can participate in a relationship 10. Minimum cardinality is the minimum number of entity instances that must participate in a relationship 11. An ID dependent entity is an entity (child) whose identifier includes the identifier of another entity (parent) 12. A weak entity is an entity whose existence depends upon another entity. All ID Dependent entities are considered weak Exercise: Now that we have done a substantial work in understanding Georgia Pacific s database needs, let us create a data model to get the holistic view. The following summarizes the database requirements of Georgia Pacific database: A team can have multiple racers Every racer can participate in multiple races For each race, the time and position of each racer is recorded The teams have an attribute called DateTeamRegistered. The racers have the attributes like RacerName, DateRacerRegistered (with the team), Paid (by the team), RacerCompany. Every Race has the attribute DateRaceOccurred. For every Race, a racer can have a Position and Time. State any additional assumptions made with respect to the cardinalities.

7 Note: Use Visio Professional 2007 for drawing the data model strictly guided by the Using Visio 2007 document at downloads page (course website), which lets you use Visio just as a drawing tool instead of as a design tool. Take Home Assignment 5 Text Chapter 5: Data Modeling with the Entity-Relationship Model This assignment is a continuation of the previous take-home assignment. Please read the solution for the previous assignment before starting this one. The following are four relations designed for little John s book store. USER_TABLE (FirstName, LastName, , CreditCardNumber, PhoneNumber, ShippingAddress1, ShippingAddress2, ShippingCity, ShippingState, ShippingZip, Password) FirstName LastName CreditCardNumber PhoneNumber ShippingAddress1 ShippingAddress2 ShippingCity ShippingState ShippingZip Password Saravanaraj Duraisamy sduraisam Lenox rd Apt 111 Atlanta GA Password1 Roger Federer rfederer1@ Lenox Rd Apt 001 Atlanta GA Password2 Rafael Nadal rnadal1@s Lenox Rd Apt 002 Atlanta GA Password3 John Travolta jtravalta@ Lenox Rd Apt 003 Atlanta GA Password4 BOOK_TABLE (ISBN, Title, Price, PublicationYear, Description, AvailableCount, AuthorFirstName, AuthorLastName, Category, Publisher) ORDER_TABLE (OrderNumber, , OrderDate, OrderQuantity, OrderCost) OrderNumber OrderDate OrderQuantity OrderCost 1 sduraisamy1@ rfederer1@stu ORDER_ITEM_TABLE (OrderNumber, ISBN, Status, OrderItemNumber, OrderItemQuantity, OrderItemCost)

8 OrderNumber ISBN Status OrderItemNumber OrderItemQuantity OrderItemCost Shipped Shipped NotShipped Now that we have done a substantial work in understanding Little John s database needs, let us create a data model to get the holistic view. Any ORDER can have multiple ORDER_ITEMS Every ORDER_ITEM belongs to a single ORDER For the attributes for different entities like BOOK, USER, ORDER and ORDER_ITEM, see the table structure above. State any additional assumptions made with respect to the cardinalities. Note: Use Visio Professional 2007 for drawing the data model strictly guided by the Using Visio 2007 document at the course website (see Schedule), which lets you use Visio just as a drawing tool instead of as a design tool.

January/February 2011

CLASS DISCUSSION AND NOTES January/February 2011 Mon Tue Wed Thu Fri 31 Feb. 1 2 3 4 AH-2 (individual) Chap. 3 Rel. Model & Normalization 7 8 9 10 11 AH-3 (team) Chap. 4 DB Design Using Normalization COURSE