DATABASE SYSTEM UNIT I

Data???

Data??? Data is any information--- that could be Recorded… Example of Data Text, Number, Image, videos, speech

Data???? data is information that has been translated into a form that is efficient for movement or processing. today's computers and transmission media, data is information converted into binary digital form. It is acceptable for data to be used as a singular subject or a plural subject. Raw data is a term used to describe data in its most basic digital format.

Database A database is a collection of information that is organized so that it can be easily accessed, managed and updated. Data is organized into rows, columns and tables, and it is indexed to make it easier to find relevant information. Data gets updated, expanded and deleted as new information is added

Database- Collection of relative data Types of Data Text & Number- Traditional DB Image, Audio, Video- Multimedia DB Satellite – GIS DB Department Store- Realtime DB Huge Data- Datawarehouse – Historical Data

Why Databases Avoid manual errors Computerized the data Need to manage the data using the programs - Define the data types - construct the data -Manipulate the data

A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.

Basic Concept Data - Information Database- Collection of Data Software- ORACLE, SQL Server 2005… Hardware- Storage Device User End User Application Developer Database Administrator

Operational Data An operational data is a database designed to integrate data from multiple sources for additional operations on the data. Its for reporting, controls and operational decision support. University – Student Data Industry – Employee Data Hospital – Patent Data

Data Independence Data independence is the type of data transparency that matters for a centralized DBMS. It refers to the immunity of user applications to changes made in the definition and organization of data.

DATABASE ARCHITECTURE

Three Levels EXTERNAL LEVEL How data is viewed by an individual user CONCEPTUAL LEVEL How data is viewed by a community of users INTERNAL LEVEL How data is physically stored

Distributed Database

Distributed Database A distributed database is a database in which portions of the database are stored in multiple physical locations and processing is distributed among multiple database nodes. The evolution of distributed database is a database in which storage devices are not all attached to a common processor. It may be stored in multiple computers, located in the same physical location; or may be dispersed over a network of interconnected computers.