Database Approach

 Database:- 

Def 1:-       

Shared collection of logically related data,  and a description of this data, designed to  meet the information needs of an  organization.

Def 2:-

     An organized collection of information in computerized format.

Def 3:-

   A Computerized representation of any organizations flow of information and storage of data.

 System catalog or metadata:-

System catalog provides  description of data to enable program-  data independence. Or data about data is called metadata.

Logically related data comprises entities,  attributes, and relationships of an  organization’s information.

Database Management System (DBMS):-

Def:-

A software system that enable user to define, create, maintain and control access to the database.

Two basic operations performed by the DBMS are:

1. Management of Data in the Database
2.  Management of Users associated with the database.

DBMS software:-

• MYSQL
• Oracle
• MariaDB

The DBMS is the software program that interact with the users application programs and the database. Typically DBMS provide the following facilities:

• DDL (Data definition language)
• DML(Data manipulation language 

DDL:-

  It allows users to define the database, usually through a data definition language.

DML:-

It allow user to insert, update, delete and retrieve data from the database, usually through a data manipulation language.   

DML provide the general inquiry facility of the data, called a query language.

Query language:-

  The query language is used to perform different operations on the databases. The most popular query language is SQL. It stand for structure query language. It is the powerful database language. The statements of SQL are written in simple English-like sentences. Some important commands of SQL are SELECT, DELETE, CREATE, MODIFY, UPDATE and INSERT etc. It is used for data definition and data manipulation.

Controlled access to database may include

Ø  A security system

§  Which prevents unauthorized users accessing the database

Ø  An integrity system

§  Which maintains the consistency of stored data

Ø  A concurrency control system

§  Which allows shared access of the database

Ø  A recovery control system

§  Which restores the database to a previous consistent state in case of hardware or software failure

Ø  A user-accessible catalog

§  Which contains description of the data in the database