Data & Databases
Basic Data Fundamentals
Data vs Information
Data: facts
Computer systems store data.
Information: facts organized for a
specific application
Information is the output of a computer
system
Data
Atomic Data
Data in units that cannot be subdivided
First Name, Price, etc.
Binary Large Objects (BLOB)
Images and figures
Pictures, Cartoons
Objects
Data and associated processes
Spreadsheet tables, graphics components
Atomic Data
Most current systems store atomic data.
Atomic data is typically made up of
characters (letters and numbers) stored in
coded groups of 8 bits called bytes.
ASCII
American Standard Code for
Information Interchange
EBCDIC Extended Binary Coded Decimal
Interchange Code
Byte
*
*
*
*
*
*
*
*
Parity Bit
7 Data Bits
27 = 128 distinct characters
Atomic Data
Because atomic variables are
made up of a relatively small
number of codes, computers
can interpret and manipulate
them
Binary Large Objects
These are typically bit mapped pictures or
images (such as FAXs) that are stored.
Parts of these pictures have meaning
(unlike atomic data). Digital pictures,
video clips, stored images and signatures
are BLOBs.
PIXEL
blobs are usually stored as pixel codes
that represent a point on a video screen
Bit Maps
1028
640
1028 x 640 = 657,920 pixels
Black & White = 1 bit per pixel
256 tone Color = 8 bits per pixel
High Resolution
Image Processing
Images cannot be processed
easily (other than displayed and
scaled) by normal technology and
usually require attached atomic
indexes. Text images can be converted although the software is not
fully reliable.
Objects
Objects combine data and the processes
that manipulate it. An example of an
object is a spreadsheet table imported
with the manipulation rules.
Encapsulation
Formal Interface for Messages
Inheritance
Object Processing
Object databases are new technologies
with immature design methodologies.
They promise extensive code reuse and
easy system development if the technology proves itself.
Data, Metadata and
Business Rules
Metadata is data about data, the structure
descriptions of the stored files. Metadata
includes location, format, field name, data
description, etc.
Business rules include editing and
processing rules as well as automatic
procedures that must be processed for
accurate data.
Data Access Technology
Flat File structures.
Data in one location; metadata and business rules in
programs
Database Management Systems
Data and metadata together; business rules in
programs
Object Oriented systems
Data, metadata and business rules together
Database Approach
Program 1
Metadata
Program 2
Metadata
Program 3
Metadata
Program 1
Program 2
Program 3
FILE SYSTEM
Data
DATABASE
MetaData
Data
Central Data with Dumb
Terminals
Data
Simple Client/Server
Multi-Tier Client/Server
Data
Business Rules
Application
Distributed Processing
Data Trends
Centralized and Client/Server systems
Multi Layered architectures
Objects and encapsulation
Data driven organizations
Data warehousing
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