What is the primary purpose of an Inverted Index?

What is the primary purpose of an Inverted Index?

• A. It maps words to documents containing it for full-text search.
• B. It maps values to rows for fast equality lookups.
• C. It is the default index type for most databases.
• D. It is used for multi-dimensional proximity queries.

Answer: (A)

An inverted index is a data structure that supports fast full-text search by mapping each word to the list of documents in which it appears. This lets you quickly locate relevant documents without scanning every document—retrieve the documents for each search term and combine them (for example, by intersecting lists for multi-term queries, or using positions for phrase searches). It’s the core mechanism behind search engines and document stores that need rapid text lookup. The other options describe different kinds of indexing or uses (general value lookups, a universal default index, or spatial/proximity indexing), which aren’t the primary purpose of an inverted index.

An inverted index is a data structure that supports fast full-text search by mapping each word to the list of documents in which it appears. This lets you quickly locate relevant documents without scanning every document—retrieve the documents for each search term and combine them (for example, by intersecting lists for multi-term queries, or using positions for phrase searches). It’s the core mechanism behind search engines and document stores that need rapid text lookup. The other options describe different kinds of indexing or uses (general value lookups, a universal default index, or spatial/proximity indexing), which aren’t the primary purpose of an inverted index.