In dense index, there is an index record for every search key value in the database. This makes searching faster but requires more space to store index records itself. Index records contain search key value and a pointer to the actual record on the disk.
In sparse index, index records are not created for every search key. An index record here contains a search key and an actual pointer to the data on the disk. To search a record, we first proceed by index record and reach at the actual location of the data. If the data we are looking for is not where we directly reach by following the index, then the system starts sequential search until the desired data is found.
you can read more from here
http://www.cs.sfu.ca/CourseCentral/354/zaiane/material/notes/Chapter11/node5.html
1st calculate
block factor for DB file = (B-H)/R = (1024-0)/100 = 10 (take floor value)
block factor for index file =(B-H)/(K+P) = (1024-0)/(9+7) =64
a) How many 1st level index blocks using dense indexing.
10,000/64 = 157 (take ceiling value)
b)How many 1st level index blocks using sparse indexing.
no. of blocks of DB = 10,000/10 =1000
so no. of sparse index blocks = 1000/64 = 16 (take ceiling value)