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
z
Duplication of data or the storing of the same data
in more than one place
z
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
z
Reps
Sales rep number, last name, first name, address,
total commission, commission rate
‹ Customers
z
Customer number, name, address, current
balance, credit limit, customer sales rep
‹ Parts
z
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
z
Order number, order date, customer number
‹ Order
z
line
Order number, part number, number units ordered,
unit price
‹ Overall
z
order total
Not stored since it can be calculated
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Database Background
‹ Database
z
Structure that can store information about
‹ Multiple
types of entities
‹ Attributes
of those entities
‹ Relationships
among entities
‹ Entity
z
Person, place, thing, or event
z
Premiere Products has sales reps, customers,
orders, and parts
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Database Background (con’t)
‹ Attribute
z
Property of an entity
z
Customer has name, street, city, et cetera
z
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
z
Association between entities
z
One-to-many relationship - rep is related to many
customers
z
Customer is related to a single rep
‹ Data
file
z
File used to store data
z
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
z
Rectangles represent entities
z
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
z
Access
z
Oracle
z
DB2
z
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
z
Tables – stores data
z
Forms – screen objects used to maintain, view, and
print from a database
z
Reports – provides formatted output
z
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:
z
Branches
z
Publishers
z
Authors
z
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
z Each occurrence of the second entity is related to
only one occurrence of the first entity
z
‹ 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
z Sharing data
z Balancing conflicting requirements
z Controlling redundancy
z Facilitating consistency
z Improving integrity
z Expanding security
z Increasing productivity
z Providing data independence
z
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Summary
‹ Disadvantages
of database processing:
z
Larger file size
z
Increased complexity
z
Greater impact of failure
z
More difficult recovery
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