Accessing a model from controller not working

Rails
1

Hi could someone please put me right. I am not having any success at
accessing my model from a controller.Please look at the code:

Model:

class Region < ActiveRecord::Base

def self.get_region_code(region)
find_by_region("#{region}")
end

end

Controller code:

@region = Region.get_region_code(@region_name)

When I try to access the contents of @region

puts @region.region

It blows up with:

NoMethodError in Admin supplierController#update

You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.region

Thankyou very much.

Paul Thompson.

2

Hi –

On Tue, 8 Jul 2008, Paul Jonathan T. wrote:

end
If region is a string, then you don’t need to quote and interpolate
it. That will just produce the same string again.

I’m not sure why you need to wrap find_by_region. Can’t you just use
that in the controller?

It blows up with:

NoMethodError in Admin supplierController#update

You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.region

That means that your call to Region.get_region_code returned nil.
You’d need to do some inspecting to see what’s in @region_name at the
time of the call.

David

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3

Hi David,

Thank you for your advice. It worked when I changed the code in the
controller to:

@region = Region.find_by_region(@region_name)

rather than the previous code. But now I am confused, because I would
have said that I am doing the identical thing. Where is my thinking
wrong? As I have used the previous method before (with a different
model and controller) and it worked just fine. The reason that I used
the previous method was that I thought it was the correct way to do
it.

Regards,
Paul

2008/7/8 David A. Black [email protected]:

4

Paul Jonathan T. wrote:

Hi David,

Thank you for your advice. It worked when I changed the code in the
controller to:

@region = Region.find_by_region(@region_name)

rather than the previous code. But now I am confused, because I would
have said that I am doing the identical thing. Where is my thinking
wrong? As I have used the previous method before (with a different
model and controller) and it worked just fine. The reason that I used
the previous method was that I thought it was the correct way to do
it.

Regards,
Paul

2008/7/8 David A. Black [email protected]:

def self.get_region_code(region)
find_by_region(“#{region}”)
end

is only different to just self.find_by_region(region) in the case that
region is not a string,
namely if it’s a nil, I imagine.

Region.find_by_region(nil) will do the SQL query “SELECT * FROM regions
where regions.region IS NULL”

while
Region.get_region_code(nil) will do the SQL query “SELECT * FROM regions
WHERE regions.region = ‘’”

So I imagine that’s your difference.

There is no region with region == ‘’, while there is one with region ==
nil
?