Select only if exist?

Rails
1

I have a table for neighborhoods with a name and an id
Also have a table for assets, each asset have a neighborhood_id
Asset model => belongs to neighborhood
Neighborhood model => has many assets
I have a page where I list all assets, and a search form to find
assets by selecting from a list of neighborhoods.
The list of neighborhoods is taken from the neighborhoods table

@list_all_neighborhoods = Neighborhood.find(:all, :order => “name”)
<%= collection_select(:asset, :neighborhood_id,
@list_all_neighborhoods, :id, :name) %>

Now if I search for a neighborhood that do not exist in one of the
assets I get a message like “no results try something else”

I want to eliminate that message and show on the search form only
neighborhoods that actually exist in the assets table.

I understand that i need to take the @list_all_neighborhoods array and
check each record to see if exist in the assets table

But I can’t make this work

I appreciate any help

Thanks

Erez

The website is online here http://www.5354.co.il
It is in Hebrew

2

On 23 Aug 2008, at 11:01, [email protected] wrote:

<%= collection_select(:asset, :neighborhood_id,
@list_all_neighborhoods, :id, :name) %>

If you add a :joins => :assets then rails will add a left join (that
will discard neighbourhoods with no assets)

Fred

3

Frederick C. wrote:

If you add a :joins => :assets then rails will add a left join (that
will discard neighbourhoods with no assets)

Fred

HI Fred,

Methinks you meant to say “inner join”.

Peace,
Phillip

4

erez.bens wrote:

@list_all_neighborhoods = Neighborhood.find(:all,
:order => “name”,

Important programming tip: All editors ship with tabs turned on, and all
programmers should never ever use tabs. They are a legacy of
programming’s
infancy, and of editors that cannot smartly indent and unindent code!

–
Phlip

5

Thank you Frad
This is working great

@list_all_neighborhoods = Neighborhood.find(:all,
:order => “name”,
:joins => :assets,
:group => :neighborhood_id)

On 23 אוגוסט, 17:11, Frederick C. [email protected]

6

On 23 Aug 2008, at 17:14, Phillip K. wrote:

Frederick C. wrote:

If you add a :joins => :assets then rails will add a left join (that
will discard neighbourhoods with no assets)

Fred

HI Fred,

Methinks you meant to say “inner join”.

Of course, brain switched off.

7

Thanks for the tip, Phlip

8

Phlip wrote:

erez.bens wrote:

@list_all_neighborhoods = Neighborhood.find(:all,
:order => “name”,

Important programming tip: All editors ship with tabs turned on, and all
programmers should never ever use tabs. They are a legacy of
programming’s
infancy, and of editors that cannot smartly indent and unindent code!

–
Phlip

Oh, puhlease don’t start this. There is, in my opinion, no more
worthless argument than about tabs versus spaces.

Peace,
Phillip