Explain the architecture of Database System? Why does the need of DBMS?

Explain the architecture of Database System

 The architecture of a database system is typically divided into three main layers: the external layer, the conceptual layer, and the internal layer.

External layer: This layer is also known as the user layer or the view layer. It consists of user applications, which interact with the database through a user interface. The external layer provides users with a simplified view of the database and hides the complex details of the conceptual and internal layers. Users can access the data they need without knowing how it is stored or retrieved.

Conceptual layer: This layer is also known as the logical layer or the schema layer. It provides a conceptual view of the entire database system, which describes the structure of the data and the relationships between different data elements. The conceptual layer defines the logical schema of the database, which specifies the data types, constraints, and relationships between tables. The conceptual layer is independent of any specific physical storage structure and is used to describe the database to the user and the external applications.

Internal layer: This layer is also known as the physical layer or the storage layer. It is responsible for managing the physical storage of the data on the computer system. The internal layer maps the logical schema defined in the conceptual layer to the physical storage structures, such as files, indexes, and data pages. The internal layer provides efficient storage, retrieval, and modification of data, and also ensures data integrity and security.

In addition to these three layers, a database system also includes a database management system (DBMS), which is responsible for controlling and managing the data in the database. The DBMS provides services such as data storage, retrieval, indexing, concurrency control, transaction management, and backup and recovery.

The need for a Database Management System (DBMS) arises due to the following reasons:

• Why does the need of DBMS? 

Data management: DBMS is designed to manage large volumes of data in an efficient and effective manner. It provides a centralized location for storing, organizing, and retrieving data from multiple sources, which makes it easier to manage and maintain data.

Data integrity: DBMS ensures that the data stored in the database is accurate and consistent. It provides mechanisms to enforce data constraints, such as primary keys, foreign keys, and check constraints, which prevent the entry of invalid data into the database.

Data security: DBMS provides security features to prevent unauthorized access to the database. It allows users to specify access control policies, which restrict access to sensitive data based on user roles and permissions.

Data sharing: DBMS enables multiple users to access the same data simultaneously. It provides concurrency control mechanisms to ensure that changes made by one user do not interfere with the work of other users.

Data backup and recovery: DBMS provides backup and recovery mechanisms to protect the data in case of system failures, hardware faults, or other disasters. It allows users to restore the database to a previous state in case of data loss or corruption.

Overall, DBMS simplifies data management and ensures data integrity, security, sharing, and recovery, which makes it an essential tool for managing large volumes of data in a variety of applications.