Text Search
MongoDB provides text indexes to support text search queries on string content. Text indexes can include any field whose value is a string or an array of string elements.
Note
MongoDB Atlas also provides Atlas Search which is a more powerful and flexible text search solution. The rest of this section discusses text indexes and not Atlas Search.
To perform text search with Mongoid, follow these steps:
Define a text index on a model.
Create the text index on the server.
Build a text search query.
Defining Text Search Index
Index definition through Mongoid is described in detail on the indexes page. Text search indexes are described in detail under text indexes in the MongoDB manual. Below is an example definition of a Band model with a text index utilizing the description field:
class Band include Mongoid::Document field :name, type: String field :description, type: String index description: 'text' end
Note that the index type (text
) must be given as a string, not as a symbol.
Creating Text Index
To create the index, invoke the db:mongoid:create_indexes
Rake task:
bundle exec rake db:mongoid:create_indexes
Querying Using Text Index
To find bands whose description contains "ounces" or its variations, use the $text operator:
Band.where('$text' => {'$search' => 'ounces'}).to_a # => [#<Band _id: 5d5341b3ce4ef35d5016746d, name: "foo", description: "ounce">]
Note that the description contains the word "ounce" even though the search query was "ounces".
Note also that when performing text search, the name of the field is not
explicitly specified - $text
operator searches all fields indexed with
the text index.