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Database & Database Management System

.

Database :


A database is a collection of  related data organized in a way that data can be easily accessed, managed and updated. Database is actually a place where related piece of information is stored and various operations can be performed on it. 
Database constitute the most important component of any computer based information system. A database may be defined as a collection of inter related relevant data stored together to server multiple application.

Feature of Database :

Share :

Data in a database is sharing among different user and application.

Validity :

Data should be correct with respect to the real word entity that they represent.

Security :

Data should be protected from unauthorized user access.

Non redundancy :

No two data items in a database should represent the same real word entity.

Consistency :

Data in a database should be some for all users. 

Database Management System (DBMS) :

Database Management System (DBMS) is a collection of interrelated data and a set of program to access those data. This is a collection of related data with an implicit meaning and hence is a database.
Database Management System are defined as the software system that allow user to define, create, maintain and control access to the database. 
Database + DBMS software = Database System

Advantage of  DBMS :

Redundancy(Duplication) : 

Data redundancy means that the same data field appears in different files and format in DBMS. The data field are highly poeticized to reduce retardant data and managed storage.

Share Data : 

All authorized users and application program can share database easily.

Data Consistency :

Data inconsistency occurs due to data redundancy. With reduced data redundancy such type of data inconsistency can be eliminated.

 Data Access :

DBMS utilizes a variety of techniques to retrieve data. With reduced data redundancy such type of data inconsistency can be eliminated.

Data Integrity :

It is easy to add new constants or change existing one.

Security :

The DBMS create the security system that enrolls user security and data privacy  and data privacy. Data being store are encrypted using various algorithm to increase security. 

Concurrent Access :

Multiple users are allowed to access data simultaneously. Concurrent access to centralized data can be allowed under some supervision.

Atomicity :

Any operation on the database must be atomic. This means operation must be either executed 100% or 0%.

Disadvantage of DBMS :

Complexity :

The provision of the functionality that is expected of a good DBMS makes the DBMS an extremely complex piece of software. Database designer, developer, database administrator and end-users must understand this functionality to take full advantage of it.

Performance :

A file based system is written for a specific application such as invoicing. A result performance is generally very good.

Higher impact of failure :

The centralization of the resource increase the vulnerability of the system. Since all user and application rely on the availability of the DBMS, the failure of any component can bring operation to a halt.

Increased cost :

The cost of DBMS varies significantly depending on the environment and functionality provided. There is also the recurrent annual maintenance cost. 



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