In a hierarchical database, a hashing function is used to locate the ________.

Concept

In a hierarchical database, records are arranged as a tree of segment occurrences. Under the Hierarchical Direct Access Method (HDAM), a randomizing or hashing routine takes the key of the top segment and converts it into a relative block number and a Root Anchor Point.

That calculation begins the root-segment access path. The result identifies a home block and anchor; when keys share that location, stored keys on the synonym chain are compared. Dependent segments are reached afterward through physical-child and physical-twin pointers.

Application

1. Supply the searched root key to the HDAM randomizing routine.

2. Use the returned relative block number and Root Anchor Point to reach the home location.

3. Compare stored keys along any synonym chain until the matching Root is identified.

Contrast

• Collision names the event in which different keys map to the same hash address; it is not a segment in the hierarchy.

• Foreign Key is a relational-database constraint and is not the access object used by HDAM.

• Records is too broad: after the root is reached, its dependent segments are obtained through hierarchy pointers rather than by another hash calculation.

Cross-check and result

The official UGC NET July 2018 Computer Science Paper II key identifies Root for this item, and the HDAM access sequence independently gives the same result. Therefore, the answer is Root.