Introduction to Databases

Three File Processing Systems

DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

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A Database System

Advantages of DBMS

• Data Independence/Reduced Maintenance• Improved Data Sharing • Increased Application Development Productivity• Enforcement of Standards• Improved Data Quality (Constraints)• Better Data Accessibility/ Responsiveness• Security, Backup/Recovery, Concurrency• Reduce Redundancy, Reduce inconsistency• Increase Integrity• Use a high level query language• Views: each user views own sub-set of the database

Evolution of Databases

Roles in a DB Environment

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• Data Administrator (DA)• Database Administrator (DBA)• Database Designers (Logical and Physical)• Application Programmers• End Users (naive and sophisticated)

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The Characteristics of Databases

• The purpose of a database is to help people track things of interest to them

• Data is stored in tables, which have rows and columns like a spreadsheet. A database may have multiple tables, where each table stores data about a different thing

• Each row in a table stores data about an occurrence or instance of the thing of interest

• A database stores data and relationships• A DBMS is the software that administers the DB

Data in Tables

The Key Characteristic of Databases: Related Tables

Databases Create Information

• Data = Recorded facts and figures• Information = Knowledge derived from

data• Databases record data, but they do so in

such a way that we can produce information from the data– The data on STUDENTs, CLASSes and

GRADEs could produce information about each student’s GPA

Database Examples

Prominent DBMS Products

• Microsoft Access

• Microsoft SQL Server– New: Microsoft SQL Server Express

• IBM DB2

• Oracle Corporation ORACLE

• Open Source: MySQL, POSTGRES

• Art Dept (Apple, Windows): Filemaker Pro

• Companies: Oracle, IBM, Microsoft,

Typical Metadata Tables