Why logical data independence important

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. Anonymous answered. 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.. The database has 3 levels as shown in the diagram below. Consider an Example of a University Database. At the different levels this is how the implementation will look like:. View 2 : studeninfo id:int. Index on the first column of Students. It allows you to provide a logical description of the database without the need to specify physical structures.

Compared to Logical Independence, it is easy to achieve physical data independence. With Physical independence, you can easily change the physical storage structures or devices with an effect on the conceptual schema. Any change done would be absorbed by the mapping between the conceptual and internal levels. Physical data independence is achieved by the presence of the internal level of the database and then the transformation from the conceptual level of the database to the internal level.

When compared to Physical Data independence, it is challenging to achieve logical data independence. Skip to content. There are two main types of data independence in a database management system that is following:. So if we see physical data independence then it assists you to separate your conceptual levels from your physical level or your internal level. In this you, without defining the physical structures, you can elaborate your logical description of your database.

Moreover, you can easily achieve physical data independence as compared to the logical database. Furthermore, with this type of data independence, you may alter the physical storage devices or physical storage structures while with the effect on the conceptual scheme. If you have altered or have performed any change, then this change will be automatically be masked by the mapping just between the levels of the conceptual and internal level.

Moreover, you can get this type of data independence by the database internal level, by transferring from the conceptual level to the internal level of the database. So basically, it allows you to alter the physical data without making ay change or modifications in the logical data or any schema.

While in doing this so, it will have not any kind of effect on any scheme or logical data. We can achieve this when we modify our physical layer to a logical layer in mapping that is PP-LL mapping and in this way we can know that whatever type of modification is don is localized.

So, whenever you are bringing change under this type of data independence then absolutely this would not change any effect on the conceptual level. So if we see the logical data independence then basically it allows altering the conceptual scheme without any type of change. Logical data is data that is about database plus it also stores the data that how the data is basically inside the disk. Hence the logical data independence will allow us to make any changes in the table without changing the data that is on the disk.

So basically there are two main themes in this type of data independence in which we change our conceptual scheme without changing the following. If we have done or made any change then it will be masked or suppressed by the mapping that will be between the conceptual and the external levels.

As we have said earlier that physical data independence is very easy to achieve while on the other hand, it may prove challenging to achieve. This type of data independence can be achieved when we modify the logical layer from the view layer that is VV-LL mapping,. Any change under the logical data independence will not cause any effect in the external level of the database. Data independence is when you have to access the data and you change the data storage without altering the ability of the program.

As a result, if this, every program will have some line that will define that how a specific file will get open, it will specify some definition of fields and some specifications of the records. While on the hand if we see the data dependency then it may be done some complications to the file. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. How to decline an interview.