The logical data independence is the key feature of database management system for maintaining data integrity and for maintaining overall effectiveness of data usage. Logical data independence is an important part of three schema architecture which allows the change or modification of conceptual schema without disturbing the external schema. The modifications in conceptual schema may include alteration of entities, attributes, relationships etc. Changing any of these elements will not disturb the external application programs which is a key advantage of logical data independence feature of database management systems.
Having logical data independence means that we can change the conceptual schema according to our want without having to bring changes to the physical schema. Logical Data Independence is important because we do not need to change the design of the database in order to add, remove or bring changes such as (adding or removing new attributes, entities, like subject details..etc) in the conceptual schema, without bringing changes to the physical schema.