1. IMS 6217: Relational Data Model 1 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Introduction to Databases—Topics Information and Data –User needs –Organization for efficient storage and retrieval Designing Database Systems The Relational Data Model Databases: Past and Future

2. IMS 6217: Relational Data Model 2 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Information and Data We will think about information as being organized data –Organized to be meaningful to the user –Organized to be easily accessible for storage and retrieval Organization adds value to the data –Lowers users' costs of perceiving the meaning of the data –Lowers costs of storing and retrieving the data

3. IMS 6217: Relational Data Model 3 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Data to Information (cont.) Information systems typically require a large up front investment to provide a stream of benefits or reduced costs in the future Careful design seeks to –Provide maximum value by identifying user needs Data Presentation to match decision making task –Reduce operating costs Automate tasks Reduce user effort

4. IMS 6217: Relational Data Model 4 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Database Management Systems (DBMS) Database management software manipulates and manages databases –Oracle, SQL Server, Access, MySQL, DBII, etc. Databases contain the data to be manipulated –One software instance can control several databases Applications communicate with the data through the database software –Multiple applications can share the same or multiple databases Users can (but usually shouldn’t) manipulate data directly through the database software

5. IMS 6217: Relational Data Model 5 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Database Management Systems (cont.) Rich history of data storage approaches In Relational DBMS the meaning of data is stored with the data Data can be addressed by its name, rather than by its place in the data order –New data fields can be added without disrupting existing programs –Programs can be changed without disrupting existing data –Characteristics of the relational data model (and object oriented data models) overcome many other problems

6. IMS 6217: Relational Data Model 6 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Designing Database Systems Database Analyst designs the database components to reflect the business requirements –Entities (tables) Attributes (fields or columns) Indices and keys –Relationships Foreign keys –Business rules –Information Products (outputs)

7. IMS 6217: Relational Data Model 7 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Designing Database Systems (cont.) System Design Goals –Stored data reflects business needs –Storage efficiency Minimum storage space Minimum data redundancy –Data is stored, retrieved, and updated efficiently –Data is accurate Key Design Goal

8. IMS 6217: Relational Data Model 8 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Designing Database Systems (cont.) We will see that these goals conflict with each other Differences are more pronounced between OLTP and OLAP systems –OLTP—Online Transaction Processing –OLAP—Online Analytical Processing Management Information Systems Business Intelligence Data Warehousing Design must make trade offs between goals Watch for these themes throughout the course

9. IMS 6217: Relational Data Model 9 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU The Relational Data Model Data is stored in rectangular storage structures called tables Each table stores data about only one kind of business entity Data in one table is related to data in other tables by common fields (keys) Rules and guidelines apply to achieve system design goals

10. IMS 6217: Relational Data Model 10 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Database Tables Record NumberLast NameFirst NameAddress 1 165JohnsonAmelia20 Castle Court 166EvansBarton12896 Viscaino Road 167BookerTroy110 West Gadsden Street 169PeriattBarry709 Royal St. 170NorbeckMatthewPSC 303 BOX 61 171FutchDavid513 Morris Rd. 173TomsonAlan3324 Mills Bayou Drive 174WestDanP. O. Box 81 176HintzWillis506 Pilot Avenue 177GaskinJerry715 Sunningdale Cove Each table contains information on one kind of entity Member Each table is rectangular Same number of columns in every row But cells may be empty Each data element (field) is described in the database

11. IMS 6217: Relational Data Model 11 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Table Relationships NumberMember NumberLNameFName 38167BookerDonna 40173TomsonMary Anne 42187McCuskerSandra 43166NevesAndrea 44190PoggeKaren 45191GajewskiLuAnn 46200AltshulerKathi Record NumberLast NameFirst NameAddress 1 165JohnsonAmelia20 Castle Court 166EvansBarton12896 Viscaino Road 167BookerTroy110 West Gadsden Street 169PeriattBarry709 Royal St. 170NorbeckMatthewPSC 303 BOX 61 171FutchDavid513 Morris Rd. 173TomsonAlan3324 Mills Bayou Drive 174WestDanP. O. Box 81 176HintzWillis506 Pilot Avenue 177GaskinJerry715 Sunningdale Cove Data in one table is related to data in other tables by common fields (keys) Member Guest

12. IMS 6217: Relational Data Model 12 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Problems What bad design decisions can we introduce into this example? –Violate design goals –Useage efficiency problems What design decisions might be good for OLTP but a problem for OLAP?

13. IMS 6217: Relational Data Model 13 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Databases: Past and Future Database developments have been characterized by: –New approaches to organizing and presenting data –Falling prices for powerful hardware –Networking to distribute data –Growth of the Internet to extend data beyond the organization's boundaries –New technologies for developing databases –New technologies for developing database-based application programs

14. IMS 6217: Relational Data Model 14 Dr. Lawrence West, MIS Dept., University of Central Florida LWEST@BUS.UCF.EDU Databases: Past and Future (cont.) What have been effects on business practices that you have seen in your lifetimes? What changes can you expect to see if past trends continue? What business changes will new technological capabilities introduce? What role do you expect to play in all of this? (And how much money do you expect to make doing it?)