table join

rubyonrails-talk
1

its my code to display list from two tables where books.subject_id=subjects.id...

def list       @subject= Subject.new       @books = Book.find(:all)       @subjects = Subject.find(:all)      @bookss=Book.find(:all, :joins=>:subject)    end how can i write code in list.rhtml to display datas from two tables... i,ve tried like this...

<% @books.each do |c|%> <%= c.title%> #column from first table <%=c.name%> #column from second table...

but ,it displays error.. "undefined method `name' for #<Book:0x4779224>" any help pls..

2

Use an association. if you;ve got

class Book    belongs_to :subject end

and then

<% @books.each do |c|%> <%= c.title%> <%=c.subject.name%> <% end %>

You don't need the the :joins option (you may want to use :include)

Fred

3

yeah..it works ...thak you ....then if i need to select datas from two tables using foreign key say for eg: like

"select table1.fieldname,table2.fieldname.... from table1 left join table2 on table2.id=table1.table_id " how can i write code for that??? thank u for your kind reply.