Transcript chapter01

Concepts of Database
Management, Fifth Edition
Chapter 1:
Introduction to Database
Management
Objectives
 Introduce
Premiere Products, the company that is
used as the basis for many of the examples
throughout the text
 Introduce
 Describe
basic database terminology
database management systems
 Explain
the advantages and disadvantages of
database processing
 Introduce
Henry Books, the company that is used
in the case that runs throughout the text
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Premiere Products
 Distributor
of appliances, housewares, and
sporting goods
 Uses
spreadsheet software to maintain
important data
 Recent
growth has made spreadsheet approach
problematic
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Figure 1.1: Sample Orders Spreadsheet
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Problems Using Spreadsheet
 Redundancy

Duplication of data or the storing of the same data
in more than one place

Occurs when the same information is stored in
more than one place
 Difficulty
 Limited
 Size
accessing data
security
limitations
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Premiere Products
Required Information
 Sales

Reps
Sales rep number, last name, first name, address,
total commission, commission rate
 Customers

Customer number, name, address, current
balance, credit limit, customer sales rep
 Parts

Inventory
Part number, description, number units on hand,
item class, warehouse number, unit price
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Figure 1.2: Premiere Products Sample Order
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Premiere Products Customer Order
 Order

Order number, order date, customer number
 Order

line
Order number, part number, number units ordered,
unit price
 Overall

order total
Not stored since it can be calculated
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Database Background
 Database

Structure that can store information about
 Multiple
types of entities
 Attributes
of those entities
 Relationships
among entities
 Entity

Person, place, thing, or event

Premiere Products has sales reps, customers,
orders, and parts
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Database Background (con’t)
 Attribute

Property of an entity

Customer has name, street, city, et cetera

May also be called a field or column
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Figure 1.3: Entities and Attributes
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Database Background (con’t.)
 Relationship

Association between entities

One-to-many relationship - rep is related to many
customers

Customer is related to a single rep
 Data
file

File used to store data

Computer counterpart to ordinary paper file
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Figure 1.4: One-to-Many Relationship
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Figure 1.5: Rep and Customer Tables
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Figure 1.5: Orders and OrderLine Tables (con’t.)
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Figure 1.5: Part Table (con’t.)
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Figure 1.6: Alternative Orders Table
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Entity-relationship Diagram
 Visual
way to represent a database

Rectangles represent entities

Lines represent relationships between
connected entities
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Figure 1.7: E-R Diagram
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Database Management Systems
 Program(s)
through which users interact with
database
 Popular
DBMSs include

Access

Oracle

DB2

SQL Server
 Premiere
Products decides to use Access
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Figure 1.8 and 1.9:
Using DBMSs in Different Ways
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Building a Database
 Database
design determines the structure of a
database
 Design
entered into DBMS during construction

Tables – stores data

Forms – screen objects used to maintain, view, and
print from a database

Reports – provides formatted output

Switchboards – a set of special forms used to
provide controlled access to the data, forms, report
and other objects in a database
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Figures 1.10 and 1.11:
Part and Order Forms
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Figure 1.12: Parts Report
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Figure 1.13: Main Switchboard
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Figure 1.14:
Main Data Switchboard
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Figure 1.15: Advantages of
Database Processing
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Figure 1.16:
Disadvantages of Database Processing
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Introduction to Henry Books
Database Case
 Book
store chain operated by Ray Henry
 Henry
decided to use database to gather and
store information on:

Branches

Publishers

Authors

Books
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Figure 1.17: Sample Branch Data
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Figure 1.17: Sample Publisher Data (con’t.)
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Figure 1.18: Sample Author Data
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Figure 1.19: Sample Book Data
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Figure 1.20: Wrote Table Relates Authors to Books
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Figure 1.20:
Inventory Table Relates Branches to Books (con’t.)
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Summary
 Nondatabase
approaches to management have
problems with replication, redundancy, sharing,
limited security, and size limitations
 Entity
- a person, place, object, event, or idea for
which you want to store and process data
 Attribute,
field, or column - a characteristic or
property of an entity
 Relationship
- an association between entities
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Summary
 One-to-many


relationship - exists when
Each occurrence of the first entity is related to many
occurrences of the second entity
Each occurrence of the second entity is related to
only one occurrence of the first entity
 Database
is a structure that can store information
about multiple types of entities
 An entity-relationship (E-R) diagram represents a
database pictorially
 Database management system (DBMS) - a
program, or a collection of programs, through
which users interact with a database
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Summary
 Advantages









to database processing:
Getting more information from the same amount of
data
Sharing data
Balancing conflicting requirements
Controlling redundancy
Facilitating consistency
Improving integrity
Expanding security
Increasing productivity
Providing data independence
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Summary
 Disadvantages
of database processing:

Larger file size

Increased complexity

Greater impact of failure

More difficult recovery
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