Ruby on Rails

On 1 December 2010 21:37, Marnen Laibow-Koser <lists@ruby-forum.com> wrote:
> Colin Law wrote in post #965538:
>> On 1 December 2010 20:15, Marnen Laibow-Koser <lists@ruby-forum.com>
>> wrote:
>>> in the correct order, then your sorting is correct.
>> Probably.  I may be wrong but I believe that postgreSQL does not even
>> guarantee that an unordered query will produce the same results if the
>> same query is run twice.
>
> Right, SQL databases cannot be assumed to guarantee this.  That's why I
> suggested creating the factories in an arbitrary order, different from
> what you want to see.

I don't think I made my point clearly. I believe that, in theory,
even by creating the objects in an arbitrary order one cannot
guarantee that an un-ordered query will not coincidentally end up with
an ordered set. I do also believe however that the probability of
this is so small as to considered negligible. It is still an
interesting academic point if not an issue in practice.

>
>>  Conceivably therefore I could test without
>> the order clause and check it fails, then, thinking I had added the
>> order clause re-run the test and find it pass.  I think though as I
>> said in an earlier post that I can use common sense and assume the
>> probability of this is so small as to be insignificant.
>
> Well, if you create the factories in order, then there's a significant
> probability of this happening...

Certainly.

Colin

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To post to this group, send email to rubyonrails-talk@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.