[Dbix-class] Exceptions per DB system

[Vangelis Katsikaros]

Hi Frew

On 04/04/2013 04:12 PM, Frew Schmidt wrote:
> On Thu, Apr 04, 2013 at 12:50:19PM +0300, Vangelis Katsikaros wrote:
>> Hi
>>
>> I sent this question about 1 month ago but got no answer. Perhaps there is
>> something more I could add to make the question more specific, or I could
>> add some information to make it more clear/easy to answer?
>>
>> Regards
>> Vangelis
>>
>
> Ok, I wrote DBIE and I regret ever having given that talk :(  DBIE is
> very not ready for public consumption.  I would not recommend anyone
> use it at all.  I have not given up on it and even use it here and
> there at work, but it is missing a few major pieces.

Oh, I see. So, it seems that there are  options
- simply catch whether an exception occurred without focusing on the 
specifics of the exception
- or end up with string matching for some common cases I see. However, I 
shouldn't rely on them to work out of the box when up|downgrading versions.

BTW, I use mysql in case this helps somehow this part of the discussion.


>   1: We need to be able to accurately introspect a significant number
>   of facts from the $dbh, such as the backend RDBMS, the version of
>   said RDBMS, and sometimes even more.  This should be it's own module
>   so that DBIE and DBIC and other modules can use it.  In the past I've
>   considered implementing it myself with reblessing, the way DBIC does
>   it, but people smarter than me recommend a more structured approach,
>   where you ask for each rebless in turn when you need it.  If I had
>   the wherewithal for it I'd pay money for this to be implemented.  It
>   is a very useful thing that a lot of people don't even know they need
>   (because they assume people only use Pg or Mysql.)
>
>   2: We need both offline (mocked) tests and online tests.  The offline
>   ones are critical for any kind of serious dev, the online are
>   critical for us to keep the project going as new databases are
>   released, so we can figure out what new errors look like.

> Some of the hard problems from when I started DBIE are actually
> solved, for instance when I started I used the abhorrent
> Exception::Class, but now that Throwable has been ported to Moo that's
> a perfectly good solution.
>
> I guess if someone out there could help me implement a design spec for
> "DBIx::DBH::Introspector" (ribasushi?  mst?) or the online/offline test
> suite for 4 exceptions and 3 databases, say:
>
>                    MySQL   PG    SQLite
>     NotUnique
>     BrokenFK
>     Truncation
>     WrongDatatype
>
> That would be enough for me to attempt going forward.  Otherwise,
> don't hold your breath, it could be a while :)

For the second part for the discussion, I am afraid I cannot add much as 
I am not experienced with internals of DBIx and the several DB* components.

In case it helps, I offer myself to chip in some manpower provided there 
is some guidance.

Thanks
Vangelis