Question $21(4$ points$)$

A disk has block size of $1024$ bytes. A file has $30,000$ EMPLOYEE records of fixed

length. Each record has the following fields: NAME $(30$ bytes$),$ SSN $(9$ bytes$),$

DEPARTMENTCODE $(9$ bytes$),$ ADDRESS $(40$ bytes$),$ PHONE $(9$ bytes$),$ BIRTHDATE

$(8$ bytes$),$ SEX $(1$ byte$),$ JOBCODE $(4$ bytes$),$ SALARY $(4$ bytes, real number$).$

Assume that you have built a dense B$+-$tree index on SSN$,$ and the B$+-$tree's leaf

nodes directly contain data records $($there is no separate data file$).$ Assume points

$($e$.$g$.$ record IDs$)$ are $10-$byte long. Assume also that you built the tree by using bulk

loading so that the nodes at each level were filled up as much as possible.

How many levels does the resulting tree have?

$|$

How many child pages does the root page have?

How many block I$/$Os are needed to search for and retrieve a record from the file

given its SSN value using the index?

How many levels would the resulting tree has with all pages $60\%$ full only?Solve all questions in image