Transcript Chapter7_Student_PPT

Chapter 7
Storing Organizational
Information - Databases
McGraw-Hill/Irwin
© 2008 The McGraw-Hill Companies, All Rights Reserved
Learning Outcomes
7.1 Define the fundamental concepts of the
relational database model
7.2 Evaluate the advantages of the
relational database model
7.3 Compare relational integrity
constraints and business-critical
integrity constraints
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Learning Outcomes
7.4 Describe the benefits of a data driven
Web site
7.5 Describe the two primary methods for
integrating information across multiple
databases
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Relational Database
Fundamentals
• Information is everywhere in an
organization
• Information is stored in databases
– Database – maintains information about
various types of objects (inventory), events
(transactions), people (employees), and
places (warehouses)
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What is the purpose of a database?
• Spreadsheet and database keep track of
things
• Spreadsheets
– Keep lists of single concept
• Databases
– Keep lists that involve multiple themes
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Relational Database
Fundamentals
• Database models include:
– Hierarchical database model – information is
organized into a tree-like structure (using
parent/child relationships) in such a way that it
cannot have too many relationships
– Network database model – a flexible way of
representing objects and their relationships; each
record may have multiple parents
– Relational database model – stores information
in the form of logically related two-dimensional
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tables
Hierarchical database model
A method for
storing data in a
database that
looks like a family
tree with one root
and a number of
branches or
subdivisions.
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Network database model
A database design for storing information by linking all records that
are related with a list of pointers.
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Relational database model
A design used in database
systems in which
relationships are created
between one or more tables
based on the idea that each
pair of tables has a field in
common.
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In the rest of this course we only focus of
Relational Databases since they are far
more applicable to businesses.
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Entities and Attributes
• Entity – a person, place, thing, transaction, or
event about which information is stored
– The rows in each table contain the entities
– In Figure 7.1 CUSTOMER includes Dave’s Sub Shop
and Pizza Palace entities
• Attributes (fields, columns) – characteristics or
properties of an entity class
– The columns in each table contain the attributes
– In Figure 7.1 attributes for CUSTOMER include
Customer ID, Customer Name, Contact Name
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Keys and Relationships
• Primary keys and foreign keys identify the
various entity classes (tables) in the
database
– Primary key – a field (or group of fields) that
uniquely identifies a given entity in a table
– Foreign key – a primary key of one table that
appears an attribute in another table and acts
to provide a logical relationship among the
two tables
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Keys and Relationships
• Potential relational database for Coca-Cola
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Another example of Relationships among
tables
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Why Relational models
• What is wrong with putting all information
in the previous slide all in ONE table?
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Relational Database Advantages
• Database advantages from a business
perspective include
– Increased flexibility
– Increased scalability and performance
– Reduced information redundancy
– Increased information integrity (quality)
– Increased information security
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Increased Flexibility
• A well-designed database should:
– Handle changes quickly and easily
– Provide users with different views
– Have only one physical view
• Physical view – deals with the physical storage of
information on a storage device such as hard drive
– Have multiple logical views
• Logical view – focuses on how users logically
access information
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Increased Scalability and Performance
• A database must scale to meet increased
demand, while maintaining acceptable
performance levels
– Scalability – refers to how well a system can
adapt to increased demands
– Performance – measures how quickly a
system performs a certain process or
transaction
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Reduced Information Redundancy
• Databases reduce information
redundancy
– Redundancy – the duplication of information
or storing the same information in multiple
places
• Inconsistency is one of the primary
problems with redundant information
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Increase Information Integrity (Quality)
• Information integrity – measures the quality
of information
• Integrity constraint – rules that help ensure
the quality of information
– Relational integrity constraint
– Business-critical integrity constraint
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Increased Information Security
• Information is an organizational asset and must
be protected
• Databases offer several security features
including:
– Password – provides authentication of the user
– Access level – determines who has access to the
different types of information
– Access control – determines types of user access,
such as read-only access
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Database Management Systems
• Database management systems (DBMS) –
software through which users and application
programs interact with a database
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DATA-DRIVEN WEB SITES
• Data-driven Web sites – an interactive Web
site kept constantly updated and relevant to
the needs of its customers through the use of
a database
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Data-Driven Web Site Business
Advantages
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Development
Content Management
Future Expandability
Minimizing Human Error
Cutting Production and Update Costs
More Efficient
Improved Stability
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Data-Driven Business Intelligence
• BI in a data-driven Web site
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Integrating Information
among Multiple Databases
• Integration – allows separate systems to
communicate directly with each other
– Forward integration – takes information
entered into a given system and sends it
automatically to all downstream systems and
processes
– Backward integration – takes information
entered into a given system and sends it
automatically to all upstream systems and
processes
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Integrating Information
among Multiple Databases
• Forward integration
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Integrating Information
among Multiple Databases
• Backward integration
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Integrating Information
among Multiple Databases
• Building a central repository specifically
for integrated information
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OPENING CASE STUDY QUESTIONS
It Takes A Village to Write an Encyclopedia
1. Identify the different types of entity classes
that might be stored in Wikipedia’s database
2. Explain why database technology is so
important to Wikipedia’s business model
3. Explain the difference between logical and
physical views and why logical views are
important to Wikipedia’s customers
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CHAPTER SEVEN CASE
Keeper of the Keys
• Almost 90 million people had their personal
information stolen or lost by organizations
– Bank of America: 1.2 million customers
– CardSystems: 40 million customers
– Citigroup: 3.9 million customers
– DSW Shoe Warehouse: 1.4 million customers.
– TJX Companies: 45.6 million customers
– Wachovia: 676,000 customers
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Chapter Seven Case Questions
1. How many organizations have your
personal information, including your Social
Security number, bank account numbers,
and credit card numbers?
2. What information is stored at your college?
Is there any chance your information could
be hacked and stolen from your college?
3. What can you do to protect yourself from
identity theft?
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Chapter Seven Case Questions
4. Do you agree or disagree with changing laws to
hold the company where the data theft occurred
accountable? Why or why not?
5. What impact would holding the company liable
where the data theft occurred have on large
organizations?
6. What impact would holding the company liable
where the data theft occurred have on small
business?
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