query optimisation

app/controllers/authors_controller.rb

@@ -16,8 +16,9 @@ class AuthorsController < ApplicationController
 	end
 
 	def index
-		@authors = Author.where(query_filter).order(:sort)
-			.paginate(page: params[:page], per_page: @preference.per_page)
+		@authors = Author.where(query_filter)
+			.order(:sort)
+			.paginate(pagination)
 		@title = "Authors"
 		respond_to do |format|
 			format.html 

app/controllers/books_controller.rb

@@ -10,8 +10,10 @@ class BooksController < ApplicationController
 	end
 
 	def index
-		@books = Book.where(query_filter).order(sort_col)
-			.paginate(page: params[:page], per_page: @preference.per_page)
+		@books = Book .where(query_filter(Book.table_name))
+			.includes(:authors, :serie) .references(:authors, :serie)
+			.order(sort_col)
+			.paginate(pagination)
 		@title = "Books"
 		respond_to do |format|
 			format.html 

app/controllers/series_controller.rb

@@ -9,8 +9,11 @@ class SeriesController < ApplicationController
 	end
 
 	def index
-		@series = Serie.where(query_filter).order(:sort)
-			.paginate(page: params[:page], per_page: @preference.per_page)
+		@series = Serie.where(query_filter(Serie.table_name))
+			.includes(books: :authors)
+			.references(:books)
+			.order(:sort)
+			.paginate(pagination)
 		@title = "Series"
 		respond_to do |format|
 			format.html 

app/helpers/preferences_helper.rb

@@ -17,18 +17,23 @@ module PreferencesHelper
 		session[:preference] = @preference.to_json
 	end
 
-	def query_filter
+	def query_filter(prefix = nil)
+		sort_col = prefix ? prefix + ".sort" : "sort"
 		conditions = Array.new
 		params = Array.new
 		if @preference.initial
-			conditions.push "UPPER(sort) LIKE ?"
+			conditions.push "UPPER(#{sort_col}) LIKE ?"
 			params.push "#{@preference.initial}%"
 		end
 		if @preference.term
-			conditions.push "sort LIKE ?"
+			conditions.push "#{sort_col} LIKE ?"
 			params.push "%#{@preference.term}%"
 		end
 		[ conditions.join(" AND ") ] + params
 	end
 
+	def pagination
+		{ page: params[:page], per_page: @preference.per_page }
+	end
+
 end