class MyModel
  def self.find_entries(params)
    fields = [:prefix, :two_letter, :three_letter]

    conditions = fields.inject([[]]) do |where, field|
      unless params[field].blank?
        where.first << "#{field} LIKE ?"
        where << "%#{params[field]}%"
      end
      where
    end

    if conditions.first.empty?
      []
    else
      conditions[0] = conditions.first.join(" AND ")
      paginate :conditions => conditions,
               :page => params[:page], :per_page => 10
    end
  end
end