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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

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Introduction to databases topics

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

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

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 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

  • Userscan (but usually shouldn’t) manipulate data directly through the database software


Database management systems cont

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

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

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 cont1

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

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

Database Tables

Each data element (field) is described in the database

Each table containsinformation on onekind of entity

Member

  • Each table is rectangular

    • Same number of columns in every row

    • But cells may be empty


Table relationships

Number

Record Number

Member Number

Last Name

LName

First Name

FName

Address 1

38

165

167

Johnson

Booker

Amelia

Donna

20 Castle Court

40

166

173

Evans

Tomson

Barton

Mary Anne

12896 Viscaino Road

167

42

187

Booker

McCusker

Troy

Sandra

110 West Gadsden Street

169

43

166

Periatt

Neves

Barry

Andrea

709 Royal St.

170

44

190

Norbeck

Pogge

Matthew

Karen

PSC 303 BOX 61

171

45

191

Futch

Gajewski

David

LuAnn

513 Morris Rd.

173

46

200

Tomson

Altshuler

Alan

Kathi

3324 Mills Bayou Drive

174

West

Dan

P. O. Box 81

176

Hintz

Willis

506 Pilot Avenue

177

Gaskin

Jerry

715 Sunningdale Cove

Table Relationships

Member

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

Guest


Problems

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?


Databases past and future

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

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?)


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