Computer Knowledge: Architecture of DBMS, Advantages and Disadvantages of DBMS for Competitive Exams

Architecture of DBMS 

The architecture of a database system provides a general framework for database system. This means that the system does not provide all the details of the data, rather it hides the details of how the data are stored and maintained.

The Architecture is divided into three levels;

1) Physical Level: It is the lowest level of data abstraction that deals with the physical representation of the database on the computer. It is also known as internal level. It defines how the data are actually stored and organised on the storage medium.

2) Logical Level: It is the overall view of the database and includes all the information that is going to be represented in the database. It describes what type of data is stored in the database, the relationship among the data without effecting to the physical level. It is also known as conceptual level.

3) View Level: This is the highest level of data abstraction which describes the interaction between the user and the system. It permits the users to access data in a way that is customised according to their needs, so that the same data cab be seen by different users in different ways, at the same time.

Advantages of DBMS 

1) Reduction in Data Redundancy: The duplication of data refers to data redundancy. DBMS cannot make separate copies of the same data. All the data is kept at a place and different applications refers to data from centrally controlled system.

2) Better Interaction with Users: In DBMS, the availability of up-to-data information improves the data to be access or respond as per user requests.

3) Improvement in Data Security: DBMS can allow the means of access to the database through the authorised channels. To ensure security, DBMS provides security tools i.e., username and password.

4) Maintenance of Data Integrity: Data integrity ensures that the data of database is accurate. In DBMS, data is centralised and used by many users at a time, it is essential to enforce integrity controls.

5) Backup and Recovery: The DBMS supports backup and recovery subsystem that is responsible to recovery data from hardware, software, virus attack and other failures.


Disadvantages of DBMS 

1) Complexity: The provision of the functionality that is expected from a good DBMS makes the DBMS an extremely complex piece of software. Failure to understand the system can lead to bad design decision, which can have serious consequences for an organisation.

2) Cost of Staff Training: Mostly DBMS are often complex systems so the training for user to use the database is required. The organisation has to pay a lot of amount for the training of staff to run the DBMS.

3) Database Failures: In most of the organisations, all data is integrated into a single database. If database is corrupted due to power failure or it is corrupted on the storage media, then our valuable data may be lost or whole system stops.

4) Cost of Maintenance: We need a high speed processor for processing large size of DBMS software. Similarly database software is also very costly. It means we must upgrade the hardware used for database management.