Joining sqlite tables?

Rails
1

Hi list,

I know a similar question has been posted recently, but I am having real
trouble relating it to my example.

I have managed to create a nested form that allows users to enter data
about Universities and resources on the same page. I want to be able to
show corresponding Uni and resource data in my view, but am running in
to a few problems.

I’m not sure if this fact impacts, but resources and universities have
their own controllers and models. I simply added a bit of code to my
unibersities controller and _form to render the resource and uni fields
on the same page.

I have created a foreign key in the ‘resource’ table, as one university
can have many resources. When trying to display the
universities/show.html.erb page I get the following error.

ActiveRecord::StatementInvalid in Universities#show

Showing
//home/resource_portal/website/app/views/universities/show.html.erb/
where line #17 raised:

|SQLite3::SQLException: no such column: resources.university_id: SELECT
“resources”.* FROM “resources” WHERE (“resources”.university_id = 7)|

Extracted source (around line #17):

|14:Country:
15:<%= @university.country %>
16: resources
17:<%= join_resources(@university) %>
18:


19:
20:
|

|
|

|Rails.root: /home/resource_portal/website|

I thought the foreign key I added to the ‘resource’ table would have
created the resources.university_id column, but I guess not.

Do I need to create some sort of new table or column? Apologies but my
DB knowledge is pretty rusty.

For reference here is the method in my helper:

def join_resources(university)
university.resources.map { |r| r.name }.join(", ")
end
end

Any help would be great.

Thanks in advance,
Jen!

2

On Wednesday, July 20, 2011 4:52:50 PM UTC-6, Jen wrote:

16: resources

Did you run: rake db:migrate (after creating the migration that creates
this
column)?

I’m assuming you added the foreign key by creating a new migration that
adds
a column to resources (as opposed to modifying existing migration
files).

Do I need to create some sort of new table or column? Apologies but my DB
knowledge is pretty rusty.

You’re on the right track. You just haven’t succeeded in creating the
foreign key column in your database. Either your migration is broken (it
creates a column w/a wrong name), or wasn’t run (you didnt’ run rake
db:migrate) or is in the wrong place (you edited an existing migration
so
that even though you ran rake db:migrate, nothing happened).

For reference here is the method in my helper:

def join_resources(university)
university.resources.map { |r| r.name }.join(", ")
end
end

This is fine.