Chapter 3

Database Management

Information Systems TodayLeonard Jessup and Joseph Valacich

Chapter 3 Objectives

• Understand why databases are important to modern organizations

• Understand how databases work

• Understand how organizations can maximize their strategic potential with databases

Database Management for Strategic Advantage

• Database – a collection of related data organized in a way to facilitate data searches

• Use databases to:– Create a book– Track book sales– Set salaries and wages– Pay employees

Database Management for Strategic Advantage

• The Database Approach: Foundational Concepts– DBMS – Database Management Systems

– Use a DBMS software to create, store, organize, and retrieve data from a single database or several databases

– Example: Microsoft Access

Database Management for Strategic Advantage

• Advantages of the Database Approach – Program-data independence– Minimal data redundancy– Improved data consistency– Improved data sharing– Increased productivity of application development– Enforcement of standards– Improved data quality– Improved data accessibility– Reduced program maintenance

Database Management for Strategic Advantage

• Effective Management of Databases– The database administrator (DBA) :

• Works with programmers and analysts to design and implement the database

• Works with users and managers to establish database policies

• Implements security features and establishes database permissions

Key Database Activities

• Entering and Querying Data– Form

– Structured Query Language (SQL)

– Query by example (QBE)

Key Database Activities

• Creating Database Reports– Report – a compilation of data that is organized and

produced in printed format

– Report Generators

Key Database Activities

• Database Design– Must be organized

– Few or no redundancies

– Data model – a map of entity relationships

– Keys

• Primary key

• Combination primary key

• Secondary key

Key Database Activities

• Database Associations– One-to-one (teams to stadiums)

– One-to-many (player to team)

– Many-to-many (players to games)

Key Database Activities

• Entity-Relationship Diagramming (ERD)– Commonly used when designing databases

– One draws entities (tables) as boxes and lines between entities to show relationships

Key Database Activities

• The Relational Model of Databases– Entities linked by a common key field

• Records = rows

• Fields = columns

– Other models exist

• Hierarchical

• Network

• Object-oriented model

Key Database Activities

• Normalization– A technique for making complex databases more efficient

and more easily handled by the DBMS

– Eliminates data redundancy

Key Database Activities• Data Dictionary

– A document that explains each piece of information in the database

• Field name• Data type

– Numeric, text, date/time– Useful for sorting and allocating storage

• Is this field a key field?• Business rules

– Update authority– Valid data values

How Organizations Get theMost from Their Data

• Linking Web Sites to Databases– Example: Amazon

• 2.5 million titles

• Managing online data effectively

How Organizations Get the Most from Their Data

• Data Mining– A method for better understanding data

– Information on customers, products, markets, etc.

– Drill down: from summary to more detailed data

– Sort and extract information

– Trends, correlations, forecasting, statistics

How Organizations Get the Most from Their Data

• Data Mining– Online Transaction Processing (OLTP)

• Immediate automated responses to user requests

• Multiple concurrent transactions

• A big part of interactive Internet e-commerce

How Organizations Get the Most from Their Data

• Data Mining– Online Analytical Processing (OLAP)

• Graphical software tools that provide complex analysis of data stored in a database

• Drills down to deeper levels of consolidation

• Time series and trend analysis

• “What if” and “why” questions

How Organizations Get the Most from Their Data

• Data Mining– Merging Transaction and Analytical Processing

• Real-time OLAP diminishes performance because the database must be “locked” during execution time

• Solution: replicate transactions on a 2nd database server

How Organizations Get the Most from Their Data

• Data Mining– Merging Transaction and Analytical Processing

• Operational Systems– Interact with customers and run a business in real time– Examples: Order processing, reservation systems

• Informational Systems– Support decision making based on stable point-in-time or

historical data

How Organizations Get the Most from Their Data

• Data Warehousing• Integrating multiple large databases into a single repository

• Queries, analysis, and processing

• Purpose: put key business information into the hands of decision makers

• Cost: millions

How Organizations Get the Most from Their Data

• Data Marts• Instead of one large data warehouse, many

organizations create multiple data marts

• Each contains a subset of the data

• Example: finance, inventory, personnel

• Each data mart is customized for particular DSS applications

• Cost: typically less than $1 million