Integration with ActiveRecord (ILIKE)

For the most basic search functionality, you can use PostgreSQL's built-in ILIKE function within a where clause. This type of search uses ActiveRecord only and does not require any additional gems.

Model

class Movie < ApplicationRecord
  scope :between, ->(from, to) { where("year >= :from AND year <= :to", from: from, to: to) }
end

Admin

Trestle.resource(:movies) do
  collection do
    Movie.order(title: :asc)
  end

  search do |query|
    query ? collection.where("title ILIKE ?", "%#{query}%") : collection
  end

  scope :all, default: true
  scope :year_1900_1949, -> { Movie.between(1900, 1949) }, label: "1900-1949"
  scope :year_1950_1999, -> { Movie.between(1950, 1999) }, label: "1950-1999"
  scope :year_2000_2049, -> { Movie.between(2000, 2049) }, label: "2000-2049"
end

Migration (Optional)

Adding a trgm index will speed up searches.

class AddTitleTrgmIndex < ActiveRecord::Migration[5.1]
  disable_ddl_transaction!

  def change
    enable_extension :pg_trgm

    reversible do |dir|
      dir.up   { execute("CREATE INDEX CONCURRENTLY movies_title_idx ON movies USING gin(title gin_trgm_ops)") }
      dir.down { execute("DROP INDEX movies_title_idx") }
    end
  end
end

See https://about.gitlab.com/2016/03/18/fast-search-using-postgresql-trigram-indexes/ for more information on this type of index.