Describe sequential file organization.  Explain the rules for

(i)  Inserting a new record.

(ii)  Deleting an existing record.       

 Ans:A sequential file consists of records organized by the order in which they were entered. The order of the records is fixed.

Records in sequential files can be written or read just sequentially.

After you placed a record into a sequential file, you cannot lengthen, shorten, or delete the record. Though, you can update (REWRITE) a record if the length does not alter. New records are added at the end of the file.

If the order in which you maintain records in a file is not significant, sequential organization is a good choice if there are many records or only a few. Sequential output is as well useful for printing reports.

(i) Inserting a new record:  Insertion poses problems if no space in which new record should go. If space, use it, if not then put new record in an overflow block.

(ii) Deleting an existing record: Deletion can be managed along with the pointer chains