Database Management System

INTRODUCTION TO DATABASE

What is Data?

 Data referred to known facts that could be

recorded and stored on computer media.

 Data consist of facts, texts, graphics,

images, sound and video segments that

have meaning in the user’s environment.

Hierarchy of Data

DATABASE

FILE

RECORD

 a collection of logically related files.

 a group of related records

 a group of related fields

FIELD

 sequence of characters that conveys meaning like word

BYTE

 comprise of 8 bits and equivalent to 1 character

BIT

 smallest data item on a computer and can have 0 or 1

Hierarchy of Data (Examples)

Data vs. Information

• Data are raw facts.

 Information is a processed data.

• Data are meaningless in its present

 Information conveys human

form.

interpretation.

Database & Database Management System

 Database is an organized collection of logically related data

or information.

 Databases are used to store, manipulate, and retrieve data

in nearly every type of organization.

 Database Management System (DBMS) is a software

package or system that facilitate the definition, construction,

manipulation and sharing functions of a computerized

database.

Typical DBMS Functions



Define a particular database in terms of its data types, structures, and

constraints



Construct or Load the initial database contents on a secondary storage

medium



Manipulate the database; (a) Retrieve, (b) Modify, and (c) Access



Share a database allows multiple users and programs to access the database

simultaneously.

Characteristics of Modern DBMS



Real World Entity



Relation-based Tables



Isolation of data and application



Less Redundancy



Consistency



Query Language

Characteristics of Modern DBMS



ACID Properties – Atomicity, Consistency, Isolation, Durability



Multiuser and Concurrent Access



Multiple Views



Security...