ActiveRecord find exceptions

ryan · January 3, 2007, 3:19pm

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?

ryan · January 3, 2007, 3:40pm

hi,

try

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

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

~gaurav

ryan · January 3, 2007, 3:56pm

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.

ryan · January 3, 2007, 4:24pm

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

ryan · January 3, 2007, 4:36pm

On 1/3/07, Ryan [email protected] wrote:

else
Model.new
end

How are other people handling situations like this?

if record = Record.find_by_id 1
record.foo
end

ryan · January 3, 2007, 5:45pm

gaurav bagga wrote:

“”

–
Posted via http://www.ruby-forum.com/.

You can also do this…

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

_Kevin

ryan · January 4, 2007, 2:20pm

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

Currently offline, but you can checkit at googles cache:

Basically what you do is:

module Kernel

Returns ‘value’ in case of an exception, otherwise returns the

execution

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