Introduction to Databases
Jan 17, 2016
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