Introduction to Database management system | Database management system

DATABASE

A database is a collection of related data.By data we mean known facts that can be recorded and that have implicit meaning. 

              EG. Consider the names,tel-phone numbers and address of the people you know. you may have recorded this data in an indexed address book or you may have stored it on a hard drive,using a personal computer and software such as Microsoft access or excel. This collection of related data with an implicit meaning is a database.

DATABASE MANAGEMENT SYSTEM- A DBMS is a collection of programs that enables users to create and maintain a database.The DBMS is a general purpose software system that facilitates the processes of defining,constructing, manipulating and sharing databases among various users and applications.Defining a database involves specifying the data types,structures and constraints of the data to be stored in the database.

OBJECTIVES OF DBMS:-

1.) To solve growing business needs of any organization .

2.) Store,retrieve or update the data.

3.) Sharing data among various users.

4.) Providing security to the database.

5.) Recovery of data in case of any failure.

REQUIREMENTS OF DBMS:-

1.) It provides data definition language.

2.) It should provide facilities for storing,updating or deleting the data.

3.) It should support multiple views of a data.

4.) It provides facilities for specifying integrity constraints so that only valid information is stored in the database.

5.) It should provide security of data and prevent un-authorized access and update.

6.) It should provide con-currency control mechanisms.

7.) Facilities for database recovery and maintenance.

MASTER FILE AND TRANSACTION FILE IN DB-

MASTER FILE-It stores static data.It changes occasionally and stores all the details of the object.

TRANSACTION FILE-The file that contains data about the costumer transaction is known transaction file.It is a dynamic file.

INSTANCE AND SCHEMA OF DB-

Collection of information stored in the database at any particular movement is known as instance of the database.The overall design of the database and its description is known as schema and it does not change frequently.

SUB-SCHEMA-It is a subset of schema and inherits the same properties that a schema has.