How to show foreign key relationship data in jqgrid? - ruby-on-rails

Question

I know how to access foreign key attributes in a scaffold index view. I can simply refer to the attributes using dot notation such as property.que.name. Given the following models:
class Priority < ActiveRecord::Base
belongs_to :que
...
end
class Que < ActiveRecord::Base
has_many :priorities
...
end
In the index view, I can do something like this to get the name value:
<td><%=h priority.que ? priority.que.name : "" %></td>
How do I do this in the jqgrid?
I tried this but the jqgrid comes back empty:
Priorities Controller:
#priorities = Priority.find(:all, :order => "position", :conditions => "multitenant_team_id = " + current_user.team.id.to_s ) do
if params[:_search] == "true"
id =~ "%#{params[:id]}%" if params[:id].present?
issue_id =~ "%#{params[:issue_id]}%" if params[:issue_id].present?
que =~ "%#{params[:que]}%" if params[:que].present?
customer =~ "%#{params[:customer]}%" if params[:customer].present?
title =~ "%#{params[:title]}%" if params[:title].present?
reporting_source =~ "%#{params[:reporting_source]}%" if params[:reporting_source].present?
priority =~ "%#{params[:priority]}%" if params[:priority].present?
product =~ "%#{params[:product]}%" if params[:product].present?
current_owner =~ "%#{params[:current_owner]}%" if params[:current_owner].present?
end
paginate :page => params[:page], :per_page => params[:rows]
order_by "#{params[:sidx]} #{params[:sord]}"
end
if request.xhr?
end
respond_to do |format|
format.html # index.html.erb
format.json { render :json => #priorities.to_jqgrid_json(
[:id, :issue_id, :que.name, :customer, :title, :reporting_source,
:priority, :product, :current_owner],
params[:page], params[:rows], #priorities.total_entries)}
format.xml { render :xml => #priorities }
end
end
Index View:
<%= jqgrid("Priorities", "priorities", "/priorities",
[
{:field => "id", :label => "ID", :width => 35, :resizable => false},
{:field => "issue_id", :label => "Issue Id"},
{:field => "que", :label => "Queue"},
{:field => "customer", :label => "Customer"},
{:field => "title", :label => "Title"},
{:field => "reporting_source", :label => "Reporting Source"},
{:field => "priority", :label => "Priority"},
{:field => "product", :label => "Product"},
{:field => "current_owner", :label => "Current Owner"}
],
{ :rows_per_page => 12, :height => 450 }
)%>
If I specify que instead of que.name, I get the data back in the grid but the Queue field shows a "#" symbol so I suspect the .to_jqgrid_json call doesn't like my syntax.
Has anyone tried this before? I hope so.

Answer 1

I fixed my problem. I ended up changing my find to a find_by_sql so I could do a left outer join on the ques table. I think there were a couple of issues. I think the *to_jqgrid_json* had problems with null foreign key values and I couldn't figure out how to get at the Que.name any other way. I'm using SQLServer so I had to use isnull(ques.name, '') to convert the null to empty space.
So I replaced my find as follows:
#priorities = Priority.find_by_sql ["select priorities.id id, issue_id, isnull(ques.name,' ') queue_name, customer, title, reporting_source, priority, product, current_owner from priorities left outer join ques on priorities.que_id = ques.id where priorities.multitenant_team_id = ? order by issue_id", current_user.team.id.to_s]
This introduced another problem in that find_by_sql returns an array which breaks the #priorities.total_entries call. So I had to replace it with array.count.
format.json { render :json => #priorities.to_jqgrid_json(
[:id, :issue_id, :queue_name, :customer, :title, :reporting_source, :priority, :product, :current_owner],
params[:page], params[:rows], #priorities.count)}
My grid looks great!
Edit
My grid LOOKS great but it doesn't paginate or sort. Back to the drawing board. :(

Answer 2

Okay, I think I fixed it for real this time.
#priorities = Priority.find(:all,
:select => "priorities.id, priorities.issue_id,
priorities.customer, priorities.title,
priorities.reporting_source, priorities.priority,
priorities.product, priorities.current_owner,
priorities.position,
isnull(ques.name,' ') queue_name",
:joins => "LEFT OUTER JOIN ques ON ques.id = priorities.que_id",
:order => "priorities.position",
:conditions => "priorities.multitenant_team_id = " + current_user.team.id.to_s ) do
I had know idea I could specify joins like this. This keeps the resultset in a format the 2dc_jqgrid plugin likes. Sorting, pagination and searching all work now. Now my grid looks good and actually works.