Data & Databases

Basic Data Fundamentals

Data vs Information

Data: facts Computer systems store data.

Information: facts organized for a specific applicationInformation is the output of a computer system

Data

Atomic DataData in units that cannot be subdivided First Name, Price, etc.

Binary Large Objects (BLOB)Images and figures Pictures, Cartoons

ObjectsData 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.

ASCIIAmerican 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 aremade 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

High Resolution

1028 x 640 = 657,920 pixelsBlack & White = 1 bit per pixel256 tone Color = 8 bits per pixel640

Image Processing

Images cannot be processed easily (other than displayed and scaled) by normal technology andusually require attached atomicindexes. Text images can be con-verted although the software is notfully 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.

EncapsulationFormal Interface for MessagesInheritance

Object Processing

Object databases are new technologieswith immature design methodologies. They promise extensive code reuse andeasy system development if the tech-nology 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 SystemsData and metadata together; business rules in programs

Object Oriented systemsData, metadata and business rules together

Database Approach

Program 1

Program 2

Program 3

Metadata

Metadata

Metadata

Data

Program 1

Program 2

Program 3

Meta- Data

Data

FILE SYSTEM

DATABASE

Central Data with Dumb Terminals

Data

Simple Client/Server

Multi-Tier Client/Server

Application

Business Rules

Data

Distributed Processing

Data Trends

Centralized and Client/Server systems

Multi Layered architecturesObjects and encapsulationData driven organizationsData warehousing

D A T A