© 2003 Prentice Hall, Inc.3-1 Chapter 3 Database Management Information Systems Today Leonard Jessup and Joseph Valacich

© 2003 Prentice Hall, Inc.3-2

© 2003 Prentice Hall, Inc.3-3 Chapter 3 Objectives Understand why databases are important to modern organizations Understand why databases are important to modern organizations Understand how databases work Understand how databases work Understand how organizations can maximize their strategic potential with databases Understand how organizations can maximize their strategic potential with databases

© 2003 Prentice Hall, Inc.3-4 Database Management for Strategic Advantage Database – a collection of related data organized in a way to facilitate data searches Database – a collection of related data organized in a way to facilitate data searches Use databases to: Use databases to:  Create a book  Track book sales  Set salaries and wages  Pay employees

© 2003 Prentice Hall, Inc.3-5 Database Management for Strategic Advantage The Database Approach: Foundational Concepts 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

© 2003 Prentice Hall, Inc.3-6 Database Management for Strategic Advantage Advantages of the Database Approach 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

© 2003 Prentice Hall, Inc.3-7 Database Management for Strategic Advantage Effective Management of Databases 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

© 2003 Prentice Hall, Inc.3-8 Key Database Activities Entering and Querying Data Entering and Querying Data  Form  Structured Query Language (SQL)  Query by example (QBE)

© 2003 Prentice Hall, Inc.3-9 Key Database Activities Creating Database Reports Creating Database Reports  Report – a compilation of data that is organized and produced in printed format  Report Generators

© 2003 Prentice Hall, Inc.3-10 Key Database Activities Database Design Database Design  Must be organized  Few or no redundancies  Data model – a map of entity relationships  Keys  Primary key  Combination primary key  Secondary key

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© 2003 Prentice Hall, Inc.3-12 Key Database Activities Database Associations Database Associations  One-to-one (teams to stadiums)  One-to-many (player to team)  Many-to-many (players to games)

© 2003 Prentice Hall, Inc.3-13 Key Database Activities Entity-Relationship Diagramming (ERD) Entity-Relationship Diagramming (ERD)  Commonly used when designing databases  One draws entities (tables) as boxes and lines between entities to show relationships

© 2003 Prentice Hall, Inc.3-14 Key Database Activities The Relational Model of Databases The Relational Model of Databases  Entities linked by a common key field  Records = rows  Fields = columns  Other models exist  Hierarchical  Network  Object-oriented model

© 2003 Prentice Hall, Inc.3-15 Key Database Activities Normalization Normalization  A technique for making complex databases more efficient and more easily handled by the DBMS  Eliminates data redundancy

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© 2003 Prentice Hall, Inc.3-18 Key Database Activities Data Dictionary Data Dictionary  A document that explains each piece of information in the database  Field name  Data type Numeric, text, date/timeNumeric, text, date/time Useful for sorting and allocating storageUseful for sorting and allocating storage  Is this field a key field?  Business rules Update authorityUpdate authority Valid data valuesValid data values

© 2003 Prentice Hall, Inc.3-19 How Organizations Get the Most from Their Data Linking Web Sites to Databases Linking Web Sites to Databases  Example: Amazon  2.5 million titles  Managing online data effectively

© 2003 Prentice Hall, Inc.3-20 How Organizations Get the Most from Their Data Data Mining 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

© 2003 Prentice Hall, Inc.3-21 How Organizations Get the Most from Their Data Data Mining Data Mining  Online Transaction Processing (OLTP)  Immediate automated responses to user requests  Multiple concurrent transactions  A big part of interactive Internet e-commerce

© 2003 Prentice Hall, Inc.3-22 How Organizations Get the Most from Their Data Data Mining 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

© 2003 Prentice Hall, Inc.3-23 How Organizations Get the Most from Their Data Data Mining 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 2 nd database server

© 2003 Prentice Hall, Inc.3-24 How Organizations Get the Most from Their Data Data Mining Data Mining  Merging Transaction and Analytical Processing  Operational Systems Interact with customers and run a business in real timeInteract with customers and run a business in real time Examples: Order processing, reservation systemsExamples: Order processing, reservation systems  Informational Systems Support decision making based on stable point-in-time or historical dataSupport decision making based on stable point-in-time or historical data

© 2003 Prentice Hall, Inc.3-25 How Organizations Get the Most from Their Data Data Warehousing 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

© 2003 Prentice Hall, Inc.3-26 How Organizations Get the Most from Their Data Data Marts 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