Q1)     What is the physical nature of a database called?
A1)     DBD
Q2)     Is it necessary that all the segments in a Dl/i database have key fields ?
A2)     It is not necessary that all the segments in the database should have key field, expect for the database.
Q3)     How man key fields and search fields can a segment have?
A3)     One key field and as many search fields in the segment can be declared.
Q4)     Is it necessary that the key field in a Dl/I database be unique?
A4)     No, it is no necessary.
Q5)     What is …