Re: [Haskelldb-users] HaskellDB in an industrial environment

[Frederik E. <fre...@a5...>]

> Santoemma Enrico wrote:
> >1) Is the library too young for a real world project? Does it work
> >with Oracle (throuhg ODBC)?
> 
> There are still significant bugs in HaskellDB, see the open bugs in
> http://sourceforge.net/tracker/?group_id=101095&atid=629040

What's the biggest bug? "No explicit grouping"?

Also, it would be nice to have somewhere -- maybe in the wiki? -- some
examples of SQL queries which can be done and which can't be done in
HaskellDB. I have a program which I've started writing using regular
SQL statements, and I'm wondering if I should translate it to
HaskellDB. Something like this would help me decide. For example here
are some queries, variables with $ represent parameters... (it's a
simple flash card program)

select id from cards where cards.id not in
    (select alg_data.id from alg_data) order by rand() limit 1

select id from alg_data where uid = $uid and
    when_eligible < $vt and
    id like $pat order by curr_delay desc limit 1

select max(show_num) from hist where (uid,id)=($uid,$id)

select min(a.s), avg(a.s), max(a.s), sum(a.s) from 
    (select id,max(show_num) s from hist where 
            uid = $uid and
            id in (select id from alg_data where
                          uid=$uid and when_eligible < $vt)
                   group by id) as a

I guess there must be a lot of benefits to using an embedded language,
I read the paper and it seems like a great idea - but if I couldn't
translate all of these, or get back the same functionality, then it
would be hard to try to port the project, so I'm reluctant to start
without more examples of what can and can't be done (and I imagine
that others are in similar positions). I'm a bit new to SQL, so please
bear with me...

Frederik

P.S. Is there just the tutorial in wiki-form? Why not put the rest of
the documentation on a wiki, so people can add to it?

P.P.S. The test application says "Server error!"...

http://jackass.tekno.chalmers.se/dp03-7/cgi/run

--
Frederik Eaton                         http://ofb.net/~frederik/