Data independence in DBMS refers to the ability to modify the schema at one level of the database system without altering the schema at the next higher level. In other words, data independence allows changes to be made to the database without affecting the programs and applications that use it. There are two types of data independence:
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Physical Data Independence: This refers to the ability to change the physical level of the database without affecting the logical or conceptual level. For example, changing the storage device of the database from magnetic tape to a hard disk would be a physical change.
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Logical Data Independence: This refers to the ability to modify the logical schema without causing application programs to be rewritten. Modifications at the logical level are necessary whenever the conceptual schema of the database changes.
Data independence is important because it allows for flexibility and scalability in the database system. It also helps to reduce database incongruity and makes it easier to modify the physical level of the database if needed to improve system performance.
