Question

Write down the difference between logical and physical data independency

Answer 1

PHYSICAL DATA INDEPENDENCE:

1.physical storage structure or devices can be changed without affecting conceptual schema.
2.Modification are performed to improve performance.
3.It is not difficult because, we have to only replace the data from one device to another device. No need to change the data only change the location of data.
4.It provides independence and immunity to conceptual and external schema.

LOGICAL DATA INDEPENDENCE:

1.Conceptual schema can be changed without affecting external schema. 2.We change/modify conceptual schema when structure of database is altered.
3.It is very difficult because, we have to see that the relationship must not changing, data is not getting lost and some other factors.
4.It only provide immunity to external schema and application program.

Answer 2

Answer:

he has told u what l will tell