Transcript Computers: Understanding Technology, 3e

Chapter 9
Database and
Information Management
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Presentation Overview
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Database Basics
Databases and Information Systems
Database Management System Software
Types of Databases
Planning and Designing Database Systems
Using Databases
Database Administration
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Database Basics
What is a database and how does it organize
information?
A database is a computerized system for storing
information in an organized manner so that it can be
searched for and retrieved when needed. Information
is stored in the form of fields, records, and files.
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Database Basics
Data vs Information
– Data – raw, unorganized content in the form of
words, numbers, sounds, or images
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Database Basics
Data vs Information
– Data – raw, unorganized content in the form of
words, numbers, sounds, or images
– Information – data associated with other useful
data on the same topic
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Database Basics
Levels of Data within a Database
– Entity – a person, place, thing, or event
– Field – a single value, such as a name, address, or
dollar amount
• data type: usually numeric or text (numbers and text)
• name: assigned by person developing the database
• size: number of characters that can be entered
– Record – related fields describing an event or
situation
– File – collection of records of the same type
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Database
Basics
Traditional
database
organizes data in
a hierarchy.
A field is the
smallest element.
Fields are within
a record. Records
are organized in
a data file.
Database is a
collection of
data files.
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Database Basics
Common
field
data
types
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Databases and
Information Systems
Management Information Systems (MIS)
– used to track and control every transaction through
a database
– transaction – any business activity central to the
nature of the enterprise
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Databases and
Information Systems
Office Information Systems
– designed as replacement for paper-based
information systems
– gives quick access to office paperwork
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Databases and
Information Systems
Decision Support Systems
– designed to help management make decisions
about an operation
– allows managers to work with “what if” scenarios
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Databases and
Information Systems
Factory Automation Systems
– runs an assembly line directly, controlling
manufacturing processes from shop-floor level of
conveyor belts and robots
– may be part of complete CIM system that controls
manufacturing process from beginning to end
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Database Management
System Software
Database Keys
– Key – attribute used to identify and provide a
means to search database
– Primary key – most important key in a field
– Data browsing – process of moving through a
database file, examining each record and looking
for information
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Database Management
System Software
Query Tools
– Query tools help users narrow down information
needed to be searched.
– A query allows users to ask questions designed to
retrieve information.
– A select command asks a database to return
records that match specific criteria.
– Joining matches data from fields in various files.
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Database Management
System Software
Structured Query Language (SQL)
This SQL statement could search for top students in a college,
with “top” defined as those students with a grade point
average (GPA) above 3.49.
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Database Management
System Software
Joining matches data
from fields in various
record files. Both
Student Personal
Records and Student
Grade Records files
would have a common
Student ID number
field, allowing
information from both
files to be returned in a
single query.
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Database Management
System Software
Metadata and the Data Dictionary
– Metadata – information about data; describes
significance of various elements of a database
– Data dictionary – a body of metadata
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Types of Databases
Flat File Databases
– database contains only one table or file
– simple and easy to use
– slower to respond because records must be
searched sequentially
– generally consume more disk space
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Types of Databases
Relational Databases
– Fields can be shared among all files in the
database, making it possible to connect them.
– A file is called a table (consists of rows and
columns).
– A record is called a tuple.
– A field is called an attribute.
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Types of Databases
Object-Oriented Databases
– stores data in the form of objects (units of objectoriented programming logic)
– object contains data related to the object and the
actions to be performed on the object
– speeds up database functions and makes database
development easier
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Types of Databases
Multimedia Databases
allows storage of pictures, movies, sounds, and
hyperlinked fields
Hybrid Databases
several different models combined to allow more
effective data handling
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Types of Databases
Operational Databases
– operational database tracks an operation or
situation, such as the inventory of a store
– distributed database
– is spread across multiple networked computers
– each computer shares a portion of the data
– can hold more information
– is cheaper
– is easier to use
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Types of Databases
Data Warehouses
– used to store data gathered from one or more
databases
– does not change, delete, or manipulate data they
store
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Planning and Designing
Database Systems
How are databases designed?
System analysts or database designers follow three
steps to plan a database
1. Create an organizational structure for the data.
2. Design an interface that makes the database userfriendly.
3. Set up reporting capabilities to allow for inquiry and
response.
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Planning and Designing
Database Systems
User requests and enters data
through the front-end
interface program. The
database
management
system
manages
the retrieval
and update of
the database
itself.
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Planning and Designing
Database Systems
Database Objects: Tools in the DBMS
– form – template that allows users to enter data
into the database
– report – formatted body of output from a
database
– data filter – filtering material in a database to
restrict a database search
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Using Databases
What are the types of data processing?
– Batch processing – occurs at a scheduled time or
when a critical point has been reached
– Transactional processing – more continuous
• real time system – data must be accurate to the second
• online transactional processing – very fast, always-on
processing
– Mixed forms of processing – transactional and batch
processing in the same system
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Using Databases
Database Users
Data entry operators type data into databases and make
sure that it is accurate. They
– add records
– modify records
– delete records
– sort records
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Database Administration
Database Administrator
– is responsible for maintaining and updating the
database and the DBMS software
– is responsible for preventing computer downtime
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Database Administration
Data Loss or Corruption
– Data corruption occurs when data is unreadable,
incomplete, or damaged.
– Backing up data is a major method for recovering lost
or corrupted data.
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Database Administration
Backup and Recovery Operations
– tape backups commonly used because they are cheap
and easy to store
– backups must be stored separately from original
material to lessen accidental data loss
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Database Administration
Database response time is the lag time between a user issuing a
command and the database system taking action.
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Database Administration
Record Locking
– occurs when users attempt to edit existing records in a
multi-user system
– allows only one user at a time to edit or delete a record
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Database Administration
Data Integrity
– data integrity – the accuracy of information provided
to database users
– redundancy – duplication of data in several fields; an
enemy of data integrity
– normalization – prevents duplicate data storage and
reduces chance that some data will not be updated
when changes are made
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Database Administration
Data Validation
– range check – allows only range of numbers to be
entered
– alphanumeric check – allows only letters of alphabet
and digits to be entered
– consistency check – checks against previously entered
data that has been validated
– completeness check – ensures every field filled out
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On the Horizon
Based on the information presented in this
chapter and your own experience, what do
you think is on the horizon?
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