How to build search form dynamically

Hi all, I want to search events based on its name, location, start date, end date and ... if i am using sql, i can do this sql= "select * from events where 1=1" if params[:name]    sql +=" name = #{params[:name]} if params[:location]    sql +=" location = #{params[:location]}

Are there other ways to construct search builder? ex: events= Events.find_by_object(search_criteria) search_criteria = {name=>params[:name],....}

Further more, I want to search event by posted, by attending, by most popular, by latest. I do it as following       logger.info "Search events for the name #{params[:name]} and sort option #{params[:sort_option]}"       @sort_option = params[:sort_option]       if "POSTED"==@sort_option         @events = current_user.events.find(:all, :conditions=>[' event_name like ?','%'+params[:name]+'%'])         # search all events current user will attend]       elsif "ATTEND"==@sort_option         @events = current_user.events.find(:all,:select=>"events.*",         :joins=>" join event_attendants on event_attendants.event_id = events.id " ,         :conditions=>[' events.event_name like ? and event_attendants.attendant_mail =? and event_attendants.aasm_state=?','%'+params[:name] +'%',current_user.email,"will_attend"])       elsif "POPULAR"==@sort_option         @events = current_network.events.find(:all,:select=>"events.*",         :joins=>" join event_attendants on event_attendants.event_id = events.id " ,         :conditions=>[' events.event_name like ? and event_attendants.aasm_state in (?)','%'+params[:name]+'%', %w{will_attend might_attend no_response}],         :group=>"event_attendants.event_id",:order=>" count(event_attendants.event_id) desc")       else         @events = current_network.events.find(:all, :conditions=>[' event_name like ?','%'+params[:name]+'%'],:order=>" created_at desc")       end

My questions + those codes are only dealing with params[:name], if some params involve ( location,...) they will become messy how to avoid it? + I want to re factor those code but really don't know how to do, or where to start? My Domain Objects Network (1) ---> (n) Event (1) --> (n) EventAttendant (n) --> User

I'm very new to Ruby and RoR. I'd appreciate your help. Thanks and regards, Van