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