Chapter 7
Storing
Organizational Information - Databases
Relational Database Fundamentals
q Information is everywhere in an
organization
q Information is stored in databases
vDatabase – maintains information about various types
of objects (inventory), events (transactions), people (employees), and places
(warehouses)HG
Database models
§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
§Relational
database model – stores information in the form of
logically related two-dimensional tables
Entities and Attributes
qEntity – a person, place, thing, transaction, or event about
which information is stored
♠The rows in each table
contain the entities
♠Customer includes Dave’s
Sub Shop and Pizza Palace entities
qAttributes
(fields, columns) –
characteristics or properties of an entity class
♠The columns in each table
contain the attributes
♠Attributes for customer
include Customer ID, Customer Name, Contact Name
Relational Database Advantages
ÁDatabase advantages from a business
perspective
q Increased flexibility
q Increased scalability and performance
q Reduced information redundancy
q Increased information integrity (quality)
q Increased information security
Increased Flexibility
©A well-designed database should:
vHandle changes quickly and easily
vProvide users with different views
vHave only one physical view
©A well-designed database should:
vHandle changes quickly and easily
vProvide users with different views
vHave only one physical view
¨Physical view – deals with the physical storage of
information on a storage device eg hard
disk
vHave multiple
logical views
¨Logical view – focuses on how users logically access information
vEg: a mail-order buss- 2 people view diff format
(logical views) but same physical view
Increased Scalability and
Performance
©A database must scale to meet
increased demand, while maintaining
acceptable performance levels
ØScalability – refers to how well a system can
adapt to increased demand
ØPerformance – measures how quickly a system
performs a certain process or transaction
Reduced
Information Redundancy
qDatabases reduce information
redundancy
Redundancy – the duplication of information
or storing the same information in multiple places
qInconsistency
is one of the primary problems with redundant information-difficult to decide which is
most current and most accurate
Increase
Information Integrity
(Quality)
Information integrity –
measures the quality of information
Integrity constraint –
rules that help ensure the
quality of information
Relational integrity
constraint-rule
that enforces basic and fundamental information-based constraints
Eg. Users cannot create an order
for a nonexistent customer ; An order cannot be shipped without an address
Business-critical integrity
constraint -rule that enforce business rules vital to an organization’s success
and often require more insight and knowledge than relational integrity
constraints
Eg. Product returns are not
accepted for fresh product 15 days after purchase; A discount maximum of 20
percent.
Database
Management Systems
Database management systems (DBMS) – software through which users and application programs interact with
a database
DATA-DRIVEN WEB SITES
qData-driven
Web sites – an interactive Web site
kept constantly updated and relevant to the needs of its customers through the
use of a database
Data-Driven Web Site Business
Advantages
vDevelopment: Allows the Web site owner to make
changes any time—all without having to rely on a developer or knowing HTML
programming.
vContent management: A static Web site requires a
programmer to make updates. This adds an unnecessary layer between the business
and its Web content, which can lead to misunderstandings and slow turnarounds
for desired changes.
vFuture expandability: Having a data-driven Web site
enables the site to grow faster than would be possible with a static site. Changing the layout, displays, and
functionality of the site (adding more features and sections) is easier with a
data-driven solution.
vMinimizing
human error:
A
well-designed, data-driven Web site will have ”error trapping” mechanisms to
ensure that required information is filled out correctly and that content is
entered and displayed in its correct format.
vCutting
production and update costs: A
data-driven Web site can be updated and ”published” by any competent data entry
or administrative person. In addition to being convenient and more affordable,
changes and updates will take a fraction of the time that they would with a
static site.
vMore
efficient: With
a data-driven solution, the system keeps track of the templates, so users do
not have to.
vImproved
Stability: With
a data-driven Web site, there is peace of mind, knowing the content is never
lost—even if your programmer is.
Data-Driven Business Intelligence
BI in a data-driven
Web site
Integrating Information among
Multiple
Databases
vIntegration – allows separate
systems to communicate directly with each other
üForward
integration – takes information entered into
a given system and sends it automatically to all downstream systems and processes
üBackward
integration – takes information entered into
a given system and sends it automatically to all upstream systems and processes
vWithout integration, an organization will:
üSpend considerable time
entering the same info in multiple system
üSuffer from the low quality
and inconsistency typically embedded in redundant info.
Forward and Backward integration
Building a central
repository specifically for integrated information
