Transcript Chapter 3 Database Management

Chapter 3
Database Management
Information Systems Today
Leonard 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:
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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
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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
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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 the
Most 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
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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