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Data independence in dbms with example pdf form pdf#
Data independence in dbms with example pdf form update#

Data independence in dbms with example pdf form update#

If we compared it to Physical independence it is difficult to achieve logical data independence.Įxample: For example, we can change the Hard disk or any other storage media.Įxample: We can add, update and delete a new attribute without a rewrite of existing application programs. If we compared it to Logical Independence it is easy to achieve physical data independence. Modification at the logical levels is important whenever the logical structures of the database are changed. Modifications made at the internal levels may or may not be needed to improve the performance of the structure. If new fields are added or deleted from the database, then you need to make changes in the Application program. If a change in the physical level occurs then it usually does not need to change at the Application program level. Mainly concerned with the structure or changing the data definition. Mainly concerned with the storage of the data. For example, we can change the location from drive C to drive D.ĭifference between Physical and Logical Data Independence Physical Data Independence

We can independently change the Location of the database from one drive of the hard disk to some another drive.

We can independently change the hashing algorithms.

We can independently change the compression techniques.

We can independently switch to some another data structure.

We can independently modify the database file organization techniques.

solve MCQ questions bank: Client server architecture, data independence.

Data independence in dbms with example pdf form pdf#

For example, we can change the Hard disk or any other storage media. Database Management System Quiz Questions and Answers PDF download with free. We can independently use a new storage device.

Some of these changes are mentioned below How Much Data Independence is possible with Physical Data Independence?ĭue to Physical data independence, there are some changes that will not affect the conceptual layer. If we compare the physical data independence with logical data Independence, then we can say that it is easy to achieve physical data independence. Figure: Physical data independence in DBMSĪlthough the independence exists but the changes made should belong to a specific domain and should not exceed the liberty offered by the physical data independence. Physical data independence facilitates the system in such a way that changes made to the internal level shall not affect the conceptual level. In the last case, external schemas that refer only to the remaining data should not be affected For example, the external schema of Figure 1.5(a) should not be.

We can add, update and delete an entity and relationship among the entities without a rewrite of existing application programs.

We can add, update and delete a new attribute without a rewrite of existing application programs.

We can break the existing record into multiple records.

How Much Data Independence is possible with Logical Data Independence? Figure: Logical data independence in DBMSĪccording to Logical Data Independence, we can change the conceptual scheme without changing the followings The changes in the conceptual model do not affect the external views. User is not aware of how the data is physically stored or conceptually managed.įigure: Implementation of Database Schema in DBMS Logical data independence

External Level – Relates to the user view.

Conceptual Level – Relates to concepts like structure and relationships of data, etc.

Physical Level – Relates to the storage of data in storage devices.

So, Database systems are designed in multi-levels. If a database system does not contain multi-layers called levels, then it becomes very difficult to make any change in the database system.

Let’s begin with the tutorial.Ī relational database is a multi-level database. “Data Independence in DBMS (Database)” is the today topic of discussion in this tutorial.