What is DatabaseOverview of DBMS and RDBMSNormalizationAbout SQL

What is Database

A database can be defined as a collection of coherent, meaningful data.

Example: A building name A flat no in the building A road name An area name A state name

What is DBMS

DBMS is a system that allowing inserting,updating,deleting and processing of data.

Benefits of DBMS The amount of data redundancy in stored data can be

reduced. Stored data can be shared by a single or multiple users. Security of data can be simply implemented Standards can be set and followed

What is RDBMS

A RDBMS is a DBMS i.e. based on the relational model as introduced by Dr. Edgar F. Codd. Strictly speaking it should also satisfy Codd’s 12 rules, but in practice there is no DBMS that satisfies all these rules.

DBMS RDBMS

DBMS does not support C/S Architecture

Most of the RDBMS supports C/S Architecture

DBMS does not support Distributed Databases

Most of the RDBMS supports distributed databases

In DBMS there is no security of data

In RDBMS there are multiple level of security Logging in at O/S level Command Level

DBMS may satisfy less than 7 to 8 rules of Dr. E. F. Codd

RDBMS usually satisfy more than 7 to 8 rules of Dr. E. F. Codd

Normalization is a technique that:

Decomposes data into two-dimensional tables, and reduce the redundancy.

SQL is a language that provides an interface to relation database systems.

Features of SQL It is non procedural language It reduces the amount of time required for

creating and maintaining systems It is an English-like language.

DDL(Data Definition Language) DML(Data Manipulation Language) DCL(Data Control Language) DQL(Data Query Language)

DDL It is a set of SQL commands used to

create,modify and delete database structures but not data.

Example:Create,Alter,Drop,Grant,Comment

DML It is the area of SQL that allows changing data

within the database. Example:

Insert,Update,Delete,Call,Lock

DCL• It is the component of SQL statement that

control access to data and to database.• Example

Commit,Savepoint,Rollback

DQL• This command is the heart of SQL .

• Example Select Retrieve data from the a database