fraasotsing

Fraasotsing, or phrase searching, is a technique in information retrieval and text search that seeks documents containing a specific, contiguous sequence of terms. Unlike simple keyword search, which returns documents containing the individual terms anywhere, phrase searching requires the words to appear in the given order and without intervening terms.

Implementation often relies on a positional inverted index. For each term, the index stores a list of documents and the positions within each document where the term occurs. A phrase query with terms t1, t2, ..., tn is evaluated by finding documents where the position of t2 is immediately after the position of t1, t3 after t2, and so on. In practice, systems may allow a slack or proximity parameter (slop) to permit limited gaps, punctuation, or variations.

User interfaces commonly support phrase searches by quoting the exact phrase. Some databases use specialized syntax or operators to denote phrases. Tokenization, stopping, stemming, and normalization influence matching: aggressive stemming may break contiguity, while removing stop words can alter phrase boundaries.

Applications include finding quotations, exact quotes in legal or academic texts, or locating product descriptions that require a specific phrase. The approach improves precision but may reduce recall if the exact sequence is rare or if minor typos exist. Proximity or fuzzy variants can help mitigate this.

See also: proximity search, boolean search, full-text search.