db_text_search

DbTextSearch

Different relational databases treat text search very differently. DbTextSearch provides a unified interface on top of ActiveRecord for SQLite, MySQL, and PostgreSQL to do:

• Case-insensitive string-in-set querying, prefix querying, and case-insensitive index creation.
• Basic full-text search for a list of terms, and FTS index creation.

Installation

Add this line to your application's Gemfile:

gem 'db_text_search', '~> 1.0'

Usage

Case-insensitive string matching

Add an index in a migration to an existing CI (case-insensitive) or CS (case-sensitive) column:

DbTextSearch::CaseInsensitive.add_index connection, :users, :username
# Options: name, unique

Or, create a new CI column:

DbTextSearch::CaseInsensitive.add_ci_text_column connection, :users, :username

Perform a search for records with column that case-insensitively equals to one of the strings in a given set:

# Find all confirmed users that have either the username Alice or Bob (case-insensitively):
DbTextSearch::CaseInsensitive.new(User.confirmed, :username).in(%w(Alice Bob))
 #=> ActiveRecord::Relation

Perform a case-insensitive prefix search:

DbTextSearch::CaseInsensitive.new(User.confirmed, :username).prefix('Jo')

See also: API documentation.

Full text search

Add an index:

DbTextSearch::FullText.add_index connection, :posts, :content
# Options: name

Perform a full-text search:

DbTextSearch::FullText.new(Post.published, :content).search('peace')
DbTextSearch::FullText.new(Post.published, :content).search(%w(love kaori))

Under the hood

Case-insensitive string matching

Case-insensitive equality methods

Column type	SQLite	MySQL	PostgreSQL
Detected types	Search / index	Detected types	Search / index	Detected types	Search / index
CI	always treated as CS	COLLATE NOCASE	default	default	CITEXT	default
CS	non-ci collations	LOWER no index	default	LOWER

Case-insensitive prefix matching (using LIKE)

Column type	SQLite	MySQL	PostgreSQL
CI	default, cannot always use an index, even for prefix queries	default	cannot use an index
CS	cannot use an index	LOWER(column text_pattern_ops)

Full-text search

MySQL

A FULLTEXT index, and a MATCH AGAINST query. MySQL v5.6.4+ is required.

PostgreSQL

A gist(to_tsvector(...)) index, and a @@ plainto_tsquery query. Methods also accept an optional pg_ts_config argument (default: "'english'") that is ignored for other databases.

SQLite

No index, a LIKE %term% query for each term joined with AND.

Development

Make sure you have a working installation of SQLite, MySQL, and PostgreSQL. After checking out the repo, run bin/setup to install dependencies. Then, run rake test_all to run the tests with all databases and gemfiles.

See the Rakefile for other available test tasks.

You can also run bin/console for an interactive prompt that will allow you to experiment.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/thredded/db_text_search. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.