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Chapter 3 Database Management Information Systems Today Leonard Jessup and Joseph Valacich © 2003 Prentice Hall, Inc. 3-1 © 2003 Prentice Hall, Inc. 3-2 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 © 2003 Prentice Hall, Inc. 3-3 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 © 2003 Prentice Hall, Inc. 3-4 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 © 2003 Prentice Hall, Inc. 3-5 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 © 2003 Prentice Hall, Inc. 3-6 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 © 2003 Prentice Hall, Inc. 3-7 Key Database Activities Entering and Querying Data Form Structured Query Language (SQL) Query by example (QBE) © 2003 Prentice Hall, Inc. 3-8 Key Database Activities Creating Database Reports Report – a compilation of data that is organized and produced in printed format Report Generators © 2003 Prentice Hall, Inc. 3-9 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 © 2003 Prentice Hall, Inc. 3-10 © 2003 Prentice Hall, Inc. 3-11 Key Database Activities Database Associations One-to-one (teams to stadiums) One-to-many (player to team) Many-to-many (players to games) © 2003 Prentice Hall, Inc. 3-12 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 © 2003 Prentice Hall, Inc. 3-13 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 © 2003 Prentice Hall, Inc. 3-14 Key Database Activities Normalization A technique for making complex databases more efficient and more easily handled by the DBMS Eliminates data redundancy © 2003 Prentice Hall, Inc. 3-15 © 2003 Prentice Hall, Inc. 3-16 © 2003 Prentice Hall, Inc. 3-17 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 © 2003 Prentice Hall, Inc. 3-18 How Organizations Get the Most from Their Data Linking Web Sites to Databases Example: Amazon 2.5 million titles Managing online data effectively © 2003 Prentice Hall, Inc. 3-19 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 © 2003 Prentice Hall, Inc. 3-20 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 © 2003 Prentice Hall, Inc. 3-21 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 © 2003 Prentice Hall, Inc. 3-22 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 © 2003 Prentice Hall, Inc. 3-23 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 © 2003 Prentice Hall, Inc. 3-24 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 © 2003 Prentice Hall, Inc. 3-25 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 © 2003 Prentice Hall, Inc. 3-26