Data Independence in DBMS

Data independence in DBMS is a DBMS property that helps you change the Database schema at one level without disturbing the schema at the next higher level of a database system.

Data independence in DBMS is of two types.

As we know that there are three levels of DBMS architecture. These levels are physical level, conceptual level, and superficial level.

Questions based on data independence are asked in the interview and GATE(CS/IT) exam. So a computer science student should prepare this topic very well.

Data independence is an important concept of designing a database management system that better performs the performance of the database.

Data Independence is also known as data independency.

Frequently Asked Questions

By the end of this data independence tutorial, students will be able to answer the following important questions on data independence in DBMS topic.

What is DBMS?
What is Database Schema?
Understanding of 3-Tier DBMS Architecture.
What is Metadata?
What is Logical Data Independence?
What is Physical Data Independence?

What is Data Independence in DBMS ?

Data independence in DBMS is a Database management system property that helps you change the database schema at one level without disturbing the schema at the next higher level of a database system.
To understand the concept of data independence in DBMS first we have to understand the logic behind this.

A database system contains lots of data. For example, it stores metadata, data about data, to find and retrieve data easily.
It is difficult to modify a set of metadata once it is stored in the database. The problem is that when database expands, changes need to be done over time to satisfy the requirements of the users. It would become a highly complex job if the entire data is dependent.
In such situation, Metadata follows a layered architecture, so that when user makes the changes in data at one layer, it doesn’t affect the data at another level.
Though this data is independent but it is mapped to each other. So this concept is known as data independence in DBMS.

Data Independence Types

There are two types of data independence in DBMS We have explained these types with example.

Logical Data independence

Logical Data Independence is the ability to change the logical level or logical schema without affecting the external level.
Logical data independence is used to describe what data is stored in the database and relationship exists among the data.
For example, a table or relation which is stored in the database and all its constraints, applied on that relation.
Logical data independence liberalizes itself from actual data stored on the disk. When user make some changes on table, it should not change the data residing on the disk.

Physical Data Independence

Actual data is stored is in bit format on the disk.
Physical data independence allows to change the physical data without disturbing the schema or logical data.
For example, if user want to upgrade the storage system it means he wants to replace hard-disks with SSD −then this change should not disturb or change the logical data or schemas.

Conclusion and Summary

I hope this data independence in DBMS tutorial will be helpful for computer science students. In this tutorial we have discussed logical data independency and physical data independency.

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