Transcript c07 - People Search

CHAPTER 7
Storing Organizational
Information - Databases
1
Learning Outcomes






Define the fundamental concepts of the relational
database model
Evaluate the advantages of the relational database
model
Compare operational integrity constraints and
business-critical integrity constraints
Describe the role and purpose of a database
management system
List and describe the four components of a
database management system
Describe the two primary methods for integrating
information across multiple databases
2
Overview
 Information is stored in databases
 Database – maintains information about
various types of objects (inventory), events
(transactions), people (employees), and
places (warehouses)
Almost every business decision is
based on information
3
Database Models
 Hierarchical database – stores related
information in terms of predefined categorical
relationships in a “tree-like” fashion
 Network database – used by a network
installation tool to allocate and track network
resources
 Relational database model – stores
information in the form of logically related
two-dimensional tables
4
Entities, Entity Classes, and Attributes
 Entity – a person, place, thing, transaction, or event about
which information is stored
 The rows in each table contain the entities
 Entity includes Dave’s Sub Shop and Pizza Palace entities
[Figure 2.6 – CUSTOMER]
 Entity class (table) – a collection of similar entities
 Entity classes include CUSTOMER, ORDER, ORDER LINE,
DISTRIBUTOR, and PRODUCT
 Attributes (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, and Phone
5
Keys and Relationships
 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
6
A relational database for Coca-Cola
Relational Database Advantages
from a business perspective
 Increased flexibility
 Increased scalability and performance
 Reduced information redundancy
 Increased information integrity (quality)
 Increased information security
8
Increased Flexibility
A well-designed database should:
 Handle changes quickly and easily
 Provide users with different views
 A database has only one physical view
 Physical view – deals with the physical storage of
information on a storage device such as a hard
disk
 A database can have multiple logical views
 Logical view – focuses on how users logically
access information to meet particular business
needs
9
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
10
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
11
Increase Information Integrity
 Information integrity – a measure
of the create
qualityanoforder
Users cannot
for a nonexistent customer
information
 Integrity constraints – rules that help ensure the
quality of information
 Operational integrity constraints – rules that
enforce basic and fundamental information-based
constraints
 Business-critical integrity constraints – rules
that enforce business rules vital to an
organization’s success and often require more
insight and knowledge than operational integrity
constraints Product returns are not accepted for
fresh product 15 days after purchase
12
Increased Information Security
 Information is an organizational asset and
must be protected
 Databases offer several security features
including:



Passwords – provide authentication of the
user
Access levels – determine who has access to
the different types of information
Access controls – Determine types of user
access, such as read-only access
13
Database management systems (DBMS) – software
through which users and application programs interact
with a database
Four components of a DBMS
Data Definition Component
helps create and maintain the data dictionary and the
structure of the database
 Data dictionary – a file that stores definitions of
information types, identifies the primary and foreign
keys, and maintains the relationships among the
tables
 The data dictionary essentially defines the logical
properties of the information that the database
contains
16
Data Manipulation Component
 Data manipulation component – allows users to
create, read, update, and delete information in a
database
 A DBMS contains several data manipulation tools:

Views – Allows users to see, change, sort, and
query the database content

Report generators

Query-by-example (QBE)

Structured query language (SQL)
17
Application Generation and Data
Administration Components
 Application generation component –
includes tools for creating visually appealing
and easy-to-use applications
 Data administration component – provides
tools for managing the overall database
environment by providing faculties for
backup, recovery, security, and performance
 IT specialists primarily use these components
20
Integrating Information among
Multiple Databases
 Organizations typically maintain multiple systems,
each with its own database
 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
21
Building a central repository specifically
for integrated information
Opening Case Study Questions Searching for Revenue - Google
1. Identify the different types of entity classes
that might be stored in Google’s indexing
database
2. Explain why database technology is so
important to Google’s business model
3. Explain the difference between logical and
physical views and why logical views are
important to Google’s employees
24