ims 6217: relational data model 1 dr. lawrence west, mis dept., university of central florida...

IMS 6217: Relational Data Model

1Dr. Lawrence West, MIS Dept., University of Central [email protected]

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



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



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



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



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



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)



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



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



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



Database Tables

Record Number Last Name First Name Address 1

165 Johnson Amelia 20 Castle Court

166 Evans Barton 12896 Viscaino Road

167 Booker Troy 110 West Gadsden Street

169 Periatt Barry 709 Royal St.

170 Norbeck Matthew PSC 303 BOX 61

171 Futch David 513 Morris Rd.

173 Tomson Alan 3324 Mills Bayou Drive

174 West Dan P. O. Box 81

176 Hintz Willis 506 Pilot Avenue

177 Gaskin Jerry 715 Sunningdale Cove

Each table containsinformation on onekind 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



Table Relationships

Number Member Number LName FName

38 167 Booker Donna

40 173 Tomson Mary Anne

42 187 McCusker Sandra

43 166 Neves Andrea

44 190 Pogge Karen

45 191 Gajewski LuAnn

46 200 Altshuler Kathi












Data in one table isrelated to data in othertables by common fields(keys)

Member

Guest



Problems

• What bad designdecisions can weintroduce into thisexample?– Violate design goals– Useage efficiency problems

• What design decisions mightbe good for OLTP but a problem for OLAP?


38 167 Booker Donna



43 166 Neves Andrea

44 190 Pogge Karen




38 167 Booker Donna



43 166 Neves Andrea

44 190 Pogge Karen



NumberNumberNumber Member NumberMember NumberMember Number LNameLNameLName FNameFNameFName

3838 167167 BookerBooker DonnaDonna

4040 173173 TomsonTomson Mary AnneMary Anne

4242 187187 McCuskerMcCusker SandraSandra

4343 166166 NevesNeves AndreaAndrea

4444 190190 PoggePogge KarenKaren

4545 191191 GajewskiGajewski LuAnnLuAnn

4646 200200 AltshulerAltshuler KathiKathi























Record NumberRecord NumberRecord Number Last NameLast NameLast Name First NameFirst NameFirst Name Address 1Address 1Address 1

165165 JohnsonJohnson AmeliaAmelia 20 Castle Court20 Castle Court

166166 EvansEvans BartonBarton 12896 Viscaino Road12896 Viscaino Road

167167 BookerBooker Troy Troy 110 West Gadsden Street110 West Gadsden Street

169169 PeriattPeriatt BarryBarry 709 Royal St.709 Royal St.

170170 NorbeckNorbeck MatthewMatthew PSC 303 BOX 61PSC 303 BOX 61

171171 FutchFutch DavidDavid 513 Morris Rd.513 Morris Rd.

173173 TomsonTomson AlanAlan 3324 Mills Bayou Drive3324 Mills Bayou Drive

174174 WestWest DanDan P. O. Box 81P. O. Box 81

176176 HintzHintz Willis Willis 506 Pilot Avenue506 Pilot Avenue

177177 GaskinGaskin JerryJerry 715 Sunningdale Cove715 Sunningdale Cove

Member

Guest



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



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?)

ims 6217: relational data model 1 dr. lawrence west, mis dept., university of central florida...

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