Data independence may be a kind of direction that keeps information separated from all programs that build use of it.This independence ensures that the information can't be redefined or reorganized by any of the programs that build use of it. In this manner, the data remains accessible, but it is also stable and cannot be corrupted by the applications.
There are 2 basic levels or varieties of independence
- Logical Data Independence- Logical knowledge (data) is data about database, that is, it stores information about how data is managed inside.Logical information independence builds it doable to vary the structure of the information severally of modifying the applications or programs that make use of the information. There is no have to be compelled to rewrite current applications as a part of the method of adding to or removing information from then system.
For example- when money-market accounts are added to banking system
- Physical Data Independence- All the schemas are logical and the actual data is stored in the bit format on the disk. Physical information independence is that the power to vary the physical information while not impacting the schema or logical information.This approach needs to do with sterilization the organization or storage procedures associated with the information, rather than modifying the data itself. Accomplishing this shift in file organization or the compartmentalization strategy used for the information doesn't need any modification to the external structure of the applications, that means that users of the applications are not likely to notice any difference at all in the function of their programs