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Beyond LIKE: Advanced Text Search and Keyword Matching in Postgres using Full Text Search
- Postgres provides built-in full-text search functions that address the limitations of basic operators like LIKE. These limitations include substring matching, ranking, synonym recognition, phrase-based matching and computationally expensive scans as data grows. Postgres’s functionality involves using the to_tsvector() function that tokenizes the video title into searchable tokens used for comparisons. Lemmatization then makes these searchable tokens lower-cased, removes suffixes and stop words by using dictionaries. The tokens are then stored in a column of type tsvector for faster searches. Furthermore, a GIN index rather than a regular B-tree index can be created on column for speedier searches. Coalesce(title, '') can be used to handle null values and matches can be found using the to_tsquery() function that converts a query string into tokens to match. PostgreSQL offers many advanced features for full-text search in the documentation.
- Basic operators like LIKE are limited in terms of substring matching, ranking, synonym recognition and phrase-based matching. Full-text search functions offer a better solution.
- Postgres provides built-in full-text search functions that address the limitations of basic operators like LIKE and computationally expensive scans as data grows.
- The basic process for full-text search in Postgres involves using the to_tsvector() function that tokenizes the video title into searchable tokens that can be compared.
- Lemmatization makes the tokens lower-cased, removes suffixes and stop words, and standardizes the data using dictionaries.
- This transformed data is then stored in a column of type tsvector for faster searches.
- A GIN index can be created on the column to speed up the text search process even more. Coalesce(title, '') can be used to handle null values.
- The to_tsquery() function converts a query string into tokens to match. Matches can be found using @@, the match symbol for full-text search.
- PostgreSQL offers many advanced features for full-text search, which users can explore in the documentation.
- In summary, a full-text search provides a more efficient way of finding matches compared to basic operators. Postgres has built-in full-text search functions that address the limitations of basic operators.
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