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Ryan

2007-Jan-03 14:19 UTC

ActiveRecord find exceptions

If find myself doing something like this a lot:

Model.find(some_criteria).field

which throws an exception if nothing is found.  I am looking for a
better way of doing something like this:

if Model.find(some_criteria)
  Model.find(some_criteria).field
else
  Model.new
end

How are other people handling situations like this?

-- 
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gaurav bagga

2007-Jan-03 14:38 UTC

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Re: ActiveRecord find exceptions

hi,

try

x=Model.find(some_criteria).field || Model.new

in case you dont require Model.new can use "" as message for nothing

~gaurav

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Ryan

2007-Jan-03 14:56 UTC

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Re: ActiveRecord find exceptions

gaurav bagga wrote:> hi,
> 
> try
> 
> x=Model.find(some_criteria).field || Model.new
> 
> in case you dont require Model.new can use "" as message for
nothing
> 
> ~gaurav
That doesn''t work for me.  I get a  ActiveRecord::RecordNotFound error.

-- 
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gaurav bagga

2007-Jan-03 15:22 UTC

head link

Re: ActiveRecord find exceptions

hi,

  in my previous reply  I dint think of the exception hence :(
so apologies

i tried something

begin
 Model.find(criteria)
rescue
""
end

other thing i tried was

Model.find_by_sql("select * from models where id = 0")

gave me empty array if entry was not there
else array with instance of model matching criteria.

hope this helps

regards
gaurav



On 1/3/07, Ryan
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:>
>
> gaurav bagga wrote:
> > hi,
> >
> > try
> >
> > x=Model.find(some_criteria).field || Model.new
> >
> > in case you dont require Model.new can use "" as message for
nothing
> >
> > ~gaurav
>
> That doesn''t work for me.  I get a  ActiveRecord::RecordNotFound
error.
>
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>
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Rick Olson

2007-Jan-03 15:35 UTC

head link

Re: ActiveRecord find exceptions

On 1/3/07, Ryan
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:>
> If find myself doing something like this a lot:
>
> Model.find(some_criteria).field
>
> which throws an exception if nothing is found.  I am looking for a
> better way of doing something like this:
>
> if Model.find(some_criteria)
>   Model.find(some_criteria).field
> else
>   Model.new
> end
>
> How are other people handling situations like this?
if record = Record.find_by_id 1
  record.foo
end

-- 
Rick Olson
http://weblog.techno-weenie.net
http://mephistoblog.com

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_Kevin

2007-Jan-03 16:44 UTC

head link

Re: ActiveRecord find exceptions

gaurav bagga wrote:> hi,
>
>   in my previous reply  I dint think of the exception hence :(
> so apologies
>
> i tried something
>
> begin
>  Model.find(criteria)
> rescue
> ""
> end
>
> other thing i tried was
>
> Model.find_by_sql("select * from models where id = 0")
>
> gave me empty array if entry was not there
> else array with instance of model matching criteria.
>
> hope this helps
>
> regards
> gaurav
>
>
>
> On 1/3/07, Ryan
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> >
> >
> > gaurav bagga wrote:
> > > hi,
> > >
> > > try
> > >
> > > x=Model.find(some_criteria).field || Model.new
> > >
> > > in case you dont require Model.new can use "" as
message for nothing
> > >
> > > ~gaurav
> >
> > That doesn''t work for me.  I get a 
ActiveRecord::RecordNotFound error.
> >
> > --
> > Posted via http://www.ruby-forum.com/.
> >
> > >
> >
You can also do this...

x=Model.find(criteria).field rescue "default value"

_Kevin


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anibalrojas-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

2007-Jan-04 13:19 UTC

head link

Re: ActiveRecord find exceptions

Sebastian Delmont has an interesting solution for this situations, he
posted it at his blog:

http://www.notsostupid.com/blog/2006/06/28/do-or-do-not-or-maybe-try/

Currently offline, but you can checkit at googles cache:

http://64.233.161.104/search?q=cache:4KIQLnwdpLYJ:www.notsostupid.com/blog/2006/06/28/do-or-do-not-or-maybe-try/+site:www.notsostupid.com+exception&hl=en&ct=clnk&cd=1&client=firefox

Basically what you do is:

module Kernel
  # Returns ''value'' in case of an exception, otherwise returns
the
execution
  # of the given block
  def try(value = nil)
    yield if block_given?
  rescue Exception => exception
    value
  end
end

Hope this simplies your exception handling for this situations

--
Aníbal Rojas
http://www.rubycorner.com
http://www.hasmanydevelopers.com/


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