OCP-043 Sorted Hash Cluster

52. You are designing an application for a telecom company and you have been asked to design a
database table to facilitate monthly bill generation. The bill would include details of customer calls, listed in
chronological order.
Which method would you follow to achieve this objective without increasing the overhead of sorting the
rows?
A.create a hash cluster to store the data
B.create an index cluster to store the data
C.create a partitioned table to store the data
D.create a sorted hash cluster to store the data
E.create a heap table with rowid to store the data
Answer: D

Creating a Sorted Hash Cluster

In a sorted hash cluster, the rows corresponding to each value of the hash function are sorted on a specified set of columns in ascending order, which can improve response time during subsequent operations on the clustered data.

For example, a telecommunications company needs to store detailed call records for a fixed number of originating telephone numbers through a telecommunications switch. From each originating telephone number there can be an unlimited number of telephone calls.

Calls are stored as they are made and processed later in first-in, first-out order (FIFO) when bills are generated for each originating telephone number. Each call has a detailed call record that is identified by a timestamp. The data that is gathered is similar to the following:

Originating Telephone NumbersCall Records Identified by Timestamp650-555-1212t0, t1, t2, t3, t4, ...650-555-1213t0, t1, t2, t3, t4, ...650-555-1214t0, t1, t2, t3, t4, .........

In the following SQL statements, the telephone_number column is the hash key. The hash cluster is sorted on the call_timestamp and call_duration columns. The number of hash keys is based on 10-digit telephone numbers.

CREATE CLUSTER call_detail_cluster (    telephone_number NUMBER,    call_timestamp NUMBER SORT,    call_duration NUMBER SORT )   HASHKEYS 10000 HASH IS telephone_number   SIZE 256; CREATE TABLE call_detail (    telephone_number     NUMBER,    call_timestamp       NUMBER   SORT,    call_duration        NUMBER   SORT,    other_info           VARCHAR2(30) )   CLUSTER call_detail_cluster (    telephone_number, call_timestamp, call_duration );

Given the sort order of the data, the following query would return the call records for a specified hash key by oldest record first.

SELECT * WHERE telephone_number = 6505551212;