Database Management System DBMS

What is Database ?

"A database is a structured collection of data. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies)." - Wikipedia

What is a Database Management System?

" A Database Management System (DBMS) is a set of programs that enables you to store, modify, and extract information from a database, it also provides users with tools to add, delete, access, modify, and analyze data stored in one location. " -Wikipedia

A DBMS is a software (and hardware) package providing the
following services:
• A data definition language (DDL).
• A data manipulation language (DML).
• Efficiency in query response and storage space.
• Maintenance of integrity and consistency.
• Concurrency control and data sharing.
• Transaction management (commit and rollback).
• Recovery from failure.
• Security.
• Data administration facilities.
• Adherence to standards (e.g. SQL).

Why Do We Need DBMS ?

Assume that a DBMS is a software (and hardware) package that
handles all the interaction of an application with the database.
1. It saves programmer time and maintenance.
2. It provides data independence.
3. It provide provides programmers with various tools.

Basic Concepts in Data Management

Field

Individual piece of data

Made up of one or more bytes, or characters

Examples: name, address, phone number

Record

Fields that are grouped together for a specific purpose

Primary key

A field, or group of fields, that uniquely identifies an individual record

Student id number for records describing students

DBMS Functions

•Manage stored data

•Transform data into information

–Transforms the way data is physically stored into whatever logical view of the data that the

user chooses

–Hides the physical details of how the data is actually stored

•Provide security

–DBMSs control who can add, view, change, or delete data in the database

•Allow multiuser access

–Controls concurrency of access to data

–Prevents one user from accessing data that has not been completely updated

•Programming and Query Language Ability

–Data Definition Language (DDL) to define and modify the structure of the data (physical

and logical views)

–Data Manipulation Language (DML) to allow the users to enter, modify, delete, and

retrieve data from thedatabase

•Provide a Data Dictionary

–Metadata – data about data

–Data dictionary contains metadata

 – data about the characteristics of databases controlled by the DBMS

Database Models

•Database model – a representation of the relationship between structures in a database
•Four common database models
–Flat file model
–Hierarchical, or tree structure, model
–Network model
–Relational model (this one is the most common)

SQL

Structured Query Language (SQL)
–Standard DDL and DML for a relational database

Used for :
Creating tables
Deleting tables
Add, change, delete, and retrieve data

Do a SQL Crash Course 

Data Mining

•Process of applying analytical and statistical methods to data to find patterns
•Retailers use data mining to determine purchasing patterns
•Pro football teams use data mining to scout the opposition

Most Commonly used Database Softwares :

• MySql
• Oracle 10g
• MS Sql Server
• MS Access

Reference Prentice Hall Inc