Data & Databases

1. Data & Databases Basic Data Fundamentals

2. Data vs Information • Data: facts Computer systems store data. • Information: facts organized for a specific application Information is the output of a computer system

3. 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

4. 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

5. Byte Parity Bit * * * * * * * * 7 Data Bits 27 = 128 distinct characters

6. Atomic Data Because atomic variables are made up of a relatively small number of codes, computers can interpret and manipulate them

7. 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. PIXELblobs are usually stored as pixel codes that represent a point on a video screen

8. Bit Maps 1028 1028 x 640 = 657,920 pixels Black & White = 1 bit per pixel 256 tone Color = 8 bits per pixel 640 High Resolution

9. 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 con- verted although the software is not fully reliable.

10. 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

11. Object Processing Object databases are new technologies with immature design methodologies. They promise extensive code reuse and easy system development if the tech- nology proves itself.

12. 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.

13. 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

14. Database Approach FILE SYSTEM Program 1 Metadata Data Program 2 Metadata Program 3 Metadata DATABASE Program 1 Meta- Data Data Program 2 Program 3

15. Central Data with Dumb Terminals Data

16. Simple Client/Server

17. Multi-Tier Client/Server Data Business Rules Application

18. Distributed Processing

19. Data Trends • Centralized and Client/Server systems • Multi Layered architectures • Objects and encapsulation • Data driven organizations • Data warehousing

20. D A T A