Introduction to DBMS

Database Management System

is a software package where you maintain and control the information to run the business and to do the day to day operations in an organized and user friendly method. In the DBMS we can back up the data, implement the security so that certain information can be modified or viewed by certain people working in the organization. In this section we learn the main concepts which we must follow while working in DBMS.
In simple words, a Database Management System is a Software program which makes the task easier, the task being adding, deleting, modifying and maintain theinformation.
Here are some database terms and concepts.
Database Concepts
Data
Databases
Entity, Attribute and Data
Entity Relationships
Data Models
DataData is information about some thing. Data gets differed from business to business,FOR EXAMPLE:- For a bus transportation company BUS, DRIVERS, CITY, SEATS OCCUPIED are data, for a computer hardware company MONITOR, CPU, HARD DISK are data.
DatabasesDatabase is an area where you save the data needed to run the business. Database provides the following features like Sharing Data,enforcing Business rules,Data security which can be applied centrally
Entity, Attribute and DataAn Entity is an object which has some attributes, FOR EXAMPLE:- A employee in an organization has a name and a particular Job.Here EMPLOYEE is an ENTITY, NAME and JOB are ATTRIBUTES. Entity - EMPLOYEEAttribute - EMP_NAME and JOBData - Name of Employee like (Mike Modano) , his Job is like (Marketing).
Entity RelationshipsDatabase contains many Entities (Tables), we can relate an entity to another,FOR EXAMPLE:- In an organization we have many departments and many employees working , here we have two entities one is EMPLOYEE and the other is DEPARTMENT. So how do we relate these two entities?We can RELATE these two entities as:-In one department there can be many employees.
The relationship between two different entities can be classified as:
1.ONE to ONE example PERSON - PASSPORT ( one individual can have only one passport)
2.ONE to MANY example DEPARTMENT - EMPLOYEE ( In one department there can be many employees working)
3.MANY to MANY example DOCTOR - PATIENT ( A doctor can have many patients and a patient can have many doctors )