Difficulty: Easy
Correct Answer: Inverted file
Explanation:
Introduction / Context:File organizations differ in how they enable access to stored records. When fast retrieval by many different keys is needed, systems add multiple indexes. The term “inverted file” describes a structure that inverts from values to lists of record identifiers across multiple keys.
Given Data / Assumptions:
Concept / Approach:An inverted file maintains, for each key value, a posting list of record pointers where that value appears. Multiple inverted lists can coexist for different fields, enabling fast lookups and Boolean combinations. This is the basis of many search engines and library catalogs. An indexed-sequential file typically has one primary sequential order with a single index; a plain indexed file may not imply multiple secondary indexes; a sequential file has no indexes at all.
Step-by-Step Solution:
Recognize the requirement: multiple indexes over one data set.Map that to “inverted file,” which stores value→document lists.Eliminate other organizations that provide fewer or no secondary indexes.Verification / Alternative check:Information retrieval literature and database textbooks use the term “inverted index” for multi-key retrieval, confirming the choice.
Why Other Options Are Wrong:
Common Pitfalls:Confusing “indexed-sequential” with “many indexes”; it focuses on maintaining sequential order with a primary index, not numerous secondary keys.
Final Answer: Inverted file
Discussion & Comments