Re: Could Someone help me with this theory question ??????

afi wrote:
> Can some one please help me with this b+ tree problem as i have just
> started database and need help to answer these questions thanks very
> much in advance I really need help now
>
> Storage Problem
>
> A company maintains the following information :
>
> On customers
> -----------------------------
> Cust Id (4 byte integer)
> CustName (var length avg 18 bytes)
> CustAddress (var length avg 60 bytes)
> AcctBal (4 byte integer)
>
> On sales
> -----------------------------
> OrderId (4 byte integer)
> CustId (foreign key to customer record)
> DateOfSale (4 byte integer)
> ProductId (4 byte integer)
> Cost (4 byte integer)
>
>
>
> Each primary file or index file has a single header record padded out
> to be 8192 bytes in size. Each record in the primary file contains 8
> bytes of additional information for control purposes. File data is
> read or written in blocks 8192 bytes in size. B-Tree nodes are also
> this size. Assume an average fill factor in B-Trees nodes of 50%. Due
> to fragmentation at the file system level blocks that are adjacent in
> files may not be adjacent on disk. The cost to read a block from disk
> is on average 5 ms.
>
>
>
>
> The company has 260,00 customers and 10,000,000 sales records. Assume
> only 10% of sales cost more than 100 euro and that on average 100,000
> sales occur every month.
>
>
>
>
> For each of these two primary files
> -------------------------------------------------
> Give the average size of a single record
> Give the number of records per 8k block
> Give the total size of each primary file
> Give both order and depth (specifying number of levels of index nodes)
> in the following indexes. HINT: use the number of records in the index
> to calculate the required depth:
> B+Tree on customer file using custid field as index key
> B+Tree on customer file using name as index key
> B+Tree on sales file using custid field as index key
> B+Tree on sales file using cost field as index key :oops: :oops:
> :oops: :oops: :oops:
>

This looks to me as practical homework assignement. Prove I am wrong.

Jan M. Nelken Received on Fri Nov 04 2005 - 18:53:03 CET