Chapter 10 Database Management
Chapter 10 Objectives
Discuss the functions
common to most DBMSs
Identify the qualities
of valuable information
Explain why data is important
to an organization
Discuss the terms character,
field, record, and file
Identify file maintenance techniques
Differentiate between a file processing system approach and the database approach
Describe characteristics of
relational, object-oriented, and multidimensional databases
Explain how to interact with Web databases
Discuss the responsibilities of
database analysts and administrators
Define the term, database
Data and Information
What is a database?
p. 514
Database software
allows you to
Collection of data
organized so
you can access,
retrieve, and
use it
Database software
also called database
management system
(DBMS)
Data and Information
How are data and information related?
p. 514 Fig. 10-1
processing
data stored on disk
Step 1. The member data, including a photograph, is entered and stored on the hard disk.
Step 2. The computer extracts the member data from disk.
Step 3. The receipt is created and printed.
Data is raw facts
Information is data that is organized
and meaningful
receipt
Computers process
data into information
Data and Information
What is data integrity?
p. 516
Degree to which data is correct
Garbage in, garbage out (GIGO)—computer phrase that means you cannot create correct information from incorrect data
Garbage out
Garbage in
Data integrity
is lost
Useful
Accessible
Organized
Data and Information
What are the qualities of valuable information?
p. 516 - 517
Timely
Verifiable
Accurate
Cost-effective
The Hierarchy of Data
What is a hierarchy?
p. 517 Fig. 10-2
Database contains files, file contains records, record contains fields, field contains characters
The Hierarchy of Data
What is a field?
p. 518 Fig. 10-3
Combination of one or more characters
Smallest unit of data user accesses
Field size defines the maximum number of characters a field can contain
Field name uniquely identifies each field
Data type specifies kind of data field contains
The Hierarchy of Data
What are common data types?
p. 518
The Hierarchy of Data
What is a record?
p. 519
Group of
related fields
Key field, or primary key,
uniquely identifies each record
The Hierarchy of Data
What is a data file?
p. 519
Collection of related records stored on disk
Maintaining Data
What is file maintenance?
p. 520
Procedures that keep data current
Maintaining Data
Why do you add records?
p. 520 Fig. 10-5
Add new record when you obtain new data
Maintaining Data
Why do you change records?
p. 521 Fig. 10-6
Correct inaccurate data
Update old data
Maintaining Data
Why do you delete records?
p. 522 Fig. 10-7
When record no longer is needed
Some programs remove record immediately, others flag record
Maintaining Data
What is validation?
p. 522 Fig. 10-8
Process of comparing data with a set of rules to find out if data is correct
Reduce data entry errors and enhance data integrity before program writes data on disk
Maintaining Data
p. 523
What are the types of validity checks?
File Processing Versus Databases
What is a file processing system?
p. 524
Each department or area within organization has own set of files
May have weaknesses
Records in one file may not relate to records in any other file
File Processing Versus Databases
What is the database approach?
p. 524 Fig. 10-9
Many programs and users can share data in database
Secures data so only authorized users can access certain data
File Processing Versus Databases
What are the strengths of the database approach?
p. 525
Reduced data redundancy
Improved data integrity
Shared
data
Easier
access
Reduced development time
File Processing Versus Databases
How do a database application and a file processing application differ in the way they store data?
p. 525 Fig. 10-10
Database Management Systems
What are popular database management systems (DBMSs)?
p. 526 Fig. 10-11
Database Management Systems
What is a data dictionary?
p. 527 Fig. 10-12
Contains data about each file in database and each field within those files
Database Management Systems
What is a query?
p. 528 Fig. 10-13
Request for specific data from a database
Query language consists of simple, English-like statements that allow users to specify data to display, print, or store
Step 1. Select the fields you want to display in the resulting query.
Step 2. Assign a name to the query, so you can open it later.
Step 3. View query on the screen.
Database Management Systems
What is a query by example (QBE)?
p. 528 Fig. 10-14
Program retrieves records that match criteria entered in form fields
Query by example screen
criteria
Query results
Has a graphical user interface that assists users with retrieving data
Database Management Systems
What is a form?
p. 530 Fig. 10-15
Window on screen that provides areas for entering or changing data in database
Used to retrieve and maintain data in a database
Form that sends data across network or Internet is called e-form, short for electronic form
Database Management Systems
What is a report generator?
p. 530 Fig. 10-16
Allows user to design a report on screen, retrieve data into report design, then display or print reports
Also called report writer
Database Management Systems
What is data security?
p. 530
Read-only privileges -
user can view data, but cannot change it
DBMS provides means to ensure only authorized users can access data
Access privileges
define activities that specific user or group of users can perform
Full-update privileges -user can view and change data
Database Management Systems
What are backup and log?
p. 531 Fig. 10-17
Backup is a copy of the entire database
Log is a listing of activities that change database contents
DBMS places three items in log: before image, actual change, and after image
before image
change
after image
Database Management Systems
What is a recovery utility?
p. 532
Rollforward— DBMS uses log to re-enter changes made to data-base since last save or backup
Also called forward
recovery
Rollback— DBMS uses log to undo any changes made to database during a certain period of time
Also called backward
recovery
Relational, Object-Oriented, and Multidimensional Databases
What is a data model?
p. 532 Fig. 10-18
Rules and standards that define how database
organizes data
Defines how users view organization of data
Three popular data models
Relational
Object-oriented
Object-relational
Multidimensional
Relational, Object-Oriented, and Multidimensional Databases
What is a relational database?
p. 533 Fig. 10-19
Stores data in tables that consist of rows and columns
Each row has primary key
Each column has unique name
Stores data relationships
Uses specialized terminology
Relational, Object-Oriented, and Multidimensional Databases
What is a relationship?
p. 533 Fig. 10-20
Connection within data
Relational, Object-Oriented, and Multidimensional Databases
What is Structured Query Language (SQL)?
p. 534 Fig. 10-21
Allows you to manage, update, and retrieve data
Has special keywords and rules included in SQL statements
SQL statement
SQL statement results
Relational, Object-Oriented, and Multidimensional Databases
What is an object-oriented database (OODB)?
p. 534
Object is item that contains data, as well as actions that read or process data
Can store more types of data
Can access data faster
Relational, Object-Oriented, and Multidimensional Databases
What are examples of applications appropriate for an
object-oriented database?
p. 534
What is a multidimensional database?
Relational, Object-Oriented, and Multidimensional Databases
p. 535
Relational, Object-Oriented, and Multidimensional Databases
What is a data warehouse?
p. 536
Web Databases
What is a Web database?
p. 536 Fig. 10-23
Database you access through the Web by filling in a form on a Web page
Usually resides on a database server, a computer that stores and provides access to a database
1. Determine the purpose of the database
4. Determine the relationships among
the tables
Design tables on paper first
Each table should contain
data about one subject
Database Administration
What are guidelines for developing a database?

p. 537
Be sure every record has a unique
primary key
Use separate fields for logically
distinct items
Do not create fields for information
that can be derived from entries in
other fields
Allow enough space for each field
Set default values for frequently
entered data
Database Administration
What is the role of the database analyst and administrator?
p. 538
Focuses on meaning and usage of data
Decides proper placement of fields, defines relationships, and identifies users’ access privileges
Creates and maintains data dictionary, manages
database security,
monitors database performance, and checks backup and recovery procedures
Summary of Database Management
Chapter 10 Complete
How data and information are
valuable assets to an organization
Methods for maintaining
high-quality data
Assessing the quality of
valuable information
Advantages of organizing
data in a database
Various types of databases
Role of the database
analysts and administrators