DBMS Schemas — Internal, Conceptual & External

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In DBMS (Database Management System), a schema refers to the logical structure of the database, which defines how the data is organized and how the different components of the database are related to each other. There are three main types of schemas in DBMS: internal schema, conceptual schema, and external schema.

  1. Internal Schema: The internal schema describes the physical storage structure of the database. It includes information about how the data is stored on disk or other storage media, such as the data file organization, indexes, and other physical details. This schema is mainly used by database administrators to optimize the performance of the database and manage storage resources.

  2. Conceptual Schema: The conceptual schema is an abstract representation of the entire database, which defines the relationships between the different data elements and provides a high-level view of the database. It describes the overall logical structure of the database, including entities, attributes, and relationships between them. This schema is mainly used by developers, designers, and stakeholders to understand the overall structure of the database.

  3. External Schema: The external schema or user schema is a specific view of the database that is tailored to meet the needs of a particular user or application. It defines how the data is presented to the user or application and specifies which data elements are accessible to them. This schema is used by end-users or application developers to access the database and perform specific tasks.

Together, these three types of schemas provide a complete and comprehensive view of the database, enabling database administrators, developers, designers, and end-users to work with the database in a more efficient and effective manner.