Hi Mike!
Cool, that you could solve the issue so fast.
I will have a look and install the new code with MySQL later this
evening (EET :-) ).
I would suggest a solution, where it is possible to disable the whole
answer counting with a setting in TurbineResources.properties.
Reasons:
- performance (in case of lots of questions)
- avoiding confusion, if (0) is shown, in case db doesn't support either
of the implemented solutions.
For performance issues it might also be a good idea to make a
possibility to define the database (or the supportance such as UNION,
OUTER JOIN, ...) in the TurbineResources.properties. Maybe a check if
the existing db-definitions in TurbineResources.properties could be
reused here
This statements are based on your email; I haven't had a look on the
source code yet.
Have fun!
Bernie
On Thu, 9 Nov 2000, Mike Haberman wrote:
>
> Hello All,
>
> I just commited a patch for DisplayTopics.java.
>
> The whole problem is getting the number of answers for
> each question.
>
> The solution in postgres is to use union selects
> The solution in mysql is to use left outer joins
> The default solution would be then to select count(*) from
> answers where answer.question_id = x (looping over all relevant questions)
>
> The patch tries the first one, then the second one, then
> finally it just returns 0 for each. I did not implement
> the last one. Hopefully, the first two will cover most.
>
> The union select statement is SQL92. The left outer join stuff
> has sql specific syntax for mysql.
>
> If someone REALLY REALLY REALLY wants the third one to work as well,
> I can do it.
>
>
> The good news is that even if your dbase doesn't support either
> of sql syntax, jyve won't be throwing exceptions at you.
>
>
> One note: I haven't tested this under mysql! (I just copied
> the old code).
>
>
> mike
>
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