Transcript chapter3 - Blog Paul Sidarta

Chapter 3
Database Management
Information Systems Today
Leonard Jessup and Joseph Valacich
© 2003 Prentice Hall, Inc.
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© 2003 Prentice Hall, Inc.
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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
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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
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Database Management for
Strategic Advantage
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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
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Database Management for
Strategic Advantage
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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
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Database Management for
Strategic Advantage
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Effective Management of Databases
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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
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Key Database Activities
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Entering and Querying Data
Form
 Structured Query Language (SQL)
 Query by example (QBE)
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Key Database Activities
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Creating Database Reports
Report – a compilation of data that is organized
and produced in printed format
 Report Generators
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Key Database Activities
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Database Design
Must be organized
 Few or no redundancies
 Data model – a map of entity relationships
 Keys
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Primary key
Combination primary key
Secondary key
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Key Database Activities
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Database Associations
One-to-one (teams to stadiums)
 One-to-many (player to team)
 Many-to-many (players to games)
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Key Database Activities
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Entity-Relationship Diagramming (ERD)
Commonly used when designing databases
 One draws entities (tables) as boxes and lines
between entities to show relationships
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Key Database Activities
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The Relational Model of Databases
Entities linked by a common key field
 Records = rows
 Fields = columns
 Other models exist
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Hierarchical
Network
Object-oriented model
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Key Database Activities
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Normalization
A technique for making complex databases
more efficient and more easily handled by the
DBMS
 Eliminates data redundancy
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Key Database Activities
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Data Dictionary
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A document that explains each piece of
information in the database
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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
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How Organizations Get the
Most from Their Data
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Linking Web Sites to Databases
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Example: Amazon
 2.5 million titles
 Managing online data effectively
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How Organizations Get the
Most from Their Data
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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
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How Organizations Get the
Most from Their Data
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Data Mining
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Online Transaction Processing (OLTP)
 Immediate automated responses to user
requests
 Multiple concurrent transactions
 A big part of interactive Internet e-commerce
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How Organizations Get the
Most from Their Data
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Data Mining
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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
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How Organizations Get the
Most from Their Data
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Data Mining
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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
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How Organizations Get the
Most from Their Data
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Data Mining
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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
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How Organizations Get the
Most from Their Data
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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
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How Organizations Get the
Most from Their Data
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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
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