Characteristics of Database Management System

 


Characteristics of Database Management System



1. Real World Entity

DBMS these days is very realistic and real-world entities are used to design its architecture. Also behavior and attributes are used by DBMS. 

To simplify it we can take an example of an organization database where employee is an entity and his employee id is an attribute.


2. Self-Describing Nature

Before DBMS, traditional file management system was used for storing information and data. There was no concept of definition in traditional file management system like we have in DBMS. 

A DBMS should be of Self- Describing nature as it not only contains the database itself but also the metadata. A metadata (data about data) defines and describes not only the extent, type, structure and format of all data but also relationship between data. 

This data represent itself that what actions should be taken on it.


3. Support ACID Properties

Any DBMS is able to support ACID (Accuracy, Completeness, Isolation, and Durability) properties. It is made sure in every DBMS that the real purpose of data should not be lost while performing transactions like delete, insert and update. 

Let us take an example; if an employee name is updated then it should make sure that there is no duplicate data and no mismatch of employee information.


4. Concurrent Use of Database

There are many chances that many users will be accessing the data at the same time. They may require altering the database system concurrently. 

At that time, DBMS supports them to concurrently use database without any problem. With the help of concurrency, economy of the system can be increased. 

For Example, employees of railway reservation system can book and access tickets for passengers concurrently. Every employee can see on his own interface that how many seats are available or bogie is fully booked.


5. Insulation Between Data and Program

Program-data independence provides a big relief to database users. In traditional file management system, structure of data files was defined in the application programs so user had to change all the programs that are using that particular data file.

But in DBMS, structure of data files is not stored in the program but it is stored in system catalogue. With the help of this, internal improvement of data efficiency or any changes in the data do not have any effect on application software.


6. Transactions

Transactions are bunch of actions that are done to bring database from one consistent state to new consistent state. Traditional file-based system did not have this feature. Transaction is always atomic that means it can never be further divided. It can only be completed or uncompleted.

For example, A person wants to credit money from his account to another person’s account. Then transaction will be complete if he sends money and other guy receives his money. Anything other than this can lead to an inconsistent transaction.


7. Data Persistence

Persistence means if the data is not removed explicitly then all the data will be maintained in DBMS. If any system failure happens then life span of data stored in the DBMS will be decided by the users directly or indirectly. 

Any data stored in the DBMS can never be lost. If system failure happens in between any transaction then it will be rolled back or fully completed, but data will never be at risk.


8. Backup and Recovery

There are many chances of failure of whole database. At that time no one will be able to get the database back and for sure company will be in a big loss. 

The only solution is to take backup of database and whenever it is needed, it can be stored back. A database must have this characteristic to enable more effectiveness.


9. Data Integrity

This is one of the most important characteristics of database management system. Integrity ensures the quality and reliability of database system. 

It protects unauthorized access of database and makes it more secure. It brings only consistence and accurate data into the database.


10. Multiple Views

Users can have multiple views of database depending on their department and interest. DBMS support multiple views of database to the users. For example, a user of teaching department will have different view and user of hostel department will have different. 

This feature helps users to have somewhat security because users of other department cannot access their files.


11. Stores Any Kind of Data

A database management system should be able to store any kind of data. It should not be restricted to employee name, salary and address. 

Any kind of data that exists in the real world can be stored in DBMS because we need to work with all kinds of data that is present around us.


12. Security

DBMS provides security to the data stored in it because all users have different rights to access database. Some of the user can access the whole database while other can access a small part of database.

For example, a computer network lecturer can only access files that are related to computer subjects but HOD of the department can access files of all subject that are related to their department.


13. Represents Complex Relationship Between Data

Data stored in a database is connected with each other and a relationship is made in between data. DBMS should be able to represent the complex relationship between data to make efficient and accurate use of data.


14. Query Language

Queries are used to retrieve and manipulate data but DBMS is armed by a strong query language that make it more effective and efficient. Users have the power to retrieve any kind of data they want from database by applying different set of queries. 

File-Based system has not this luxury of query language.

Comments

Post a Comment

Popular posts from this blog

Limitations of the File-Based Approach

  Limitations of the File-Based Approach This brief description of traditional file-based systems should be sufficient to discuss the limitations of this approach .  1 . Separation and isolation of data When data is isolated in separate files, it is more difficult to access data that should be available. With file systems, such processing is difficult. The application developer must synchronize the processing of two files to ensure the correct data is extracted. This difficulty is compounded if we require data from more than two files. 2 . Duplication of data Owing to the decentralized approach taken by each department, the file-based approach encouraged, if not necessitated, the uncontrolled duplication of data . Uncontrolled duplication of data is undesirable for several reasons, including: Duplication is wasteful. It costs time and money to enter the data more than once.  It takes up additional storage space, again with associated costs. Often, the duplication of data...
Read more

The Three-Level ANSI-SPARC Architecture

Image
  The Three-Level ANSI-SPARC Architecture For our purposes, the fundamental point of these and later reports is the identification of three levels of abstraction, that is, three distinct levels at which data items can be described. The levels form a three-level architecture comprising an external, a conceptual, and an internal level . The way users perceive the data is called the external level.  The way the DBMS and the operating system perceive the data is the internal level, where the data is actually stored using the data structures and file organizations . The conceptual level provides both the mapping and the desired independence between the external and internal levels.  The objective of the three-level architecture is to separate each user’s view of the database from the way the database is physically represented. There are several reasons why this separation is desirable: Each user should be able to access the same data, but have a different customized view...
Read more

Roles of DA , DBA , Database Designer , Application Developers and Users

  Roles of Data Administrator(DA) , Database Administrator (DBA) , Database Designer , Application Developers and Users Here i will explain all peoples who are involved in DBMS in two parts  Actors on the scene Workers behind the scene . Actors on the scene Roles of Data Administrator The Data Administrator (DA) is responsible for the management of the data resource including database planning, development and maintenance of standards, policies and procedures, and conceptual/logical database design.  The DA consults with and advises senior managers, ensuring that the direction of database development will ultimately support corporate objectives. "Person in the organization who controls the data of the database refers data administrator." DA determines what data to be stored in database based on requirement of the organization. DA works on such as requirements gathering, analysis, and design phases. DA does not to be a technical person, any kind of knowledge about database...
Read more