What is physical and logical data independence in DBMS?

Logical data independence: The ability to change the logical (conceptual) schema without changing the External schema (User View) is called logical data independence. Physical data independence: The ability to change the physical schema without changing the logical schema is called physical data independence.

What is the difference between physical and logical database schema?

Physical schema represents the actual connection to the data source or data target. Logical schema represents the logical name associated to that source or target.

What are the different levels of database schema?

Summary

• There are mainly three levels of data abstraction: Internal Level, Conceptual or Logical Level or External or View level.
• The internal schema defines the physical storage structure of the database.
• The conceptual schema describes the Database structure of the whole database for the community of users.

What is the concept of data independence and explain its importance in database environment?

Data Independence is defined as a property of DBMS that helps you to change the Database schema at one level of a database system without requiring to change the schema at the next higher level. Data independence helps you to keep data separated from all programs that make use of it.

What is a physical schema in DBMS?

Physical schema is a term used in data management to describe how data is to be represented and stored (files, indices, et al.) in secondary storage using a particular database management system (DBMS) (e.g., Oracle RDBMS, Sybase SQL Server, etc.).

How view is related to data independence?

Views provide data independence to an application as the application depends on a view but not on a real table. Therefore, any change in the table will not affect the application, and an application will always be independent of the table schema design.

What is physical data independence in DBMS Mcq?

Physical Data Independence: The ability to change the internal schema without having to change the conceptual schema.

What is physical level in DBMS?

Physical Level It is also known as the internal level. The physical level describes how data is actually stored in the database. In the lowest level, this data is stored in the external hard drives in the form of bits and at a little high level, it can be said that the data is stored in files and folders.

What are the three levels of DBMS schema?

There are 3 levels in the schema architecture of DBMS: physical level, logical level and view level (arranged from the lowest to highest level). Instances of why we may want to do any sort of Data modification in the physical level- We may want to alter or change the data in the physical level.

What is conceptual schema in DBMS?

The conceptual schema describes the Database structure of the whole database for the community of users. This schema hides information about the physical storage structures and focuses on describing data types, entities, relationships, etc. This logical level comes between the user level and physical storage view.

What happens when you modify the physical level of a schema?

Hence, modification in the Physical level should not result in any changes in the Logical or View levels. There are 3 levels in the schema architecture of DBMS: physical level, logical level and view level (arranged from the lowest to highest level).

What is physical data independence in DBMS?

Relations stored as unordered files. Index on the first column of Students. Physical data independence helps you to separate conceptual levels from the internal/physical levels. It allows you to provide a logical description of the database without the need to specify physical structures.