revdb_query in function silently errs out

[Maarten Koopmans]

Well, I just opened and closed a new connection inside the function, and
that works like it should. So it looks like I'll make a stack-based
"verify-connection" function (and it's little brother, clean-up connection).

--Maarten

On Mon, May 9, 2011 at 11:39 PM, Pete <pete at mollysrevenge.com> wrote:

> Got it, thanks.  I've experienced similar things in LC.  Is it possible
> that
> the data coming back from your query could include NULL characters?  I've
> seen that cause problems like this.
>
> Some SQL dbs do have connection timeouts but I don't think SQlite does.
>
> Might be able to figure out more if you post a snippet of your code.
>
> Pete
> Molly's Revenge <http://www.mollysrevenge.com>
>
>
>
>
> On Mon, May 9, 2011 at 2:22 PM, Maarten Koopmans <
> maarten.koopmans at gmail.com
> > wrote:
>
> > I am doing a revdb_query in a function; my database id is a global. I
> > am in a handler that has done a few queries, then calls said function.
> > The sql has been reduced to a dummy select * from table. Earlier
> > cursors are closed, and I use sqlite.
> >
> > I use 'answer question ...' and the one right after the query ( and
> > all logic after that) is never reached. One thing I'll try is
> > open/close a connection in the function.
> >
> > --Maarten
> >
> > On Monday, May 9, 2011, Pete <pete at mollysrevenge.com> wrote:
> > > Hi Maarten,
> > > Can you describe in a bit more detail what happens?  Are you using
> > > revDataFromQuery or revQueryDatabase to issue the SELECT?  If it errors
> > out
> > > silently, how do you discover that it didn't work?
> > > Pete
> > > Molly's Revenge <http://www.mollysrevenge.com>
> > >
> > >
> > >
> > >
> > > On Mon, May 9, 2011 at 1:27 PM, Maarten Koopmans <
> > maarten.koopmans at gmail.com
> > >> wrote:
> > >
> > >> I'll try that and maybe sqlyoga, but I am using sqlite with only
> > >> milliseconds in between. But query results as arrays etc. Sounds like
> > >> a missing piece, so while typing I have decided to give sqlyoga a try.
> > >>
> > >> --Maarten
> > >>
> > >> On Monday, May 9, 2011, Bob Sneidar <bobs at twft.com> wrote:
> > >> > How long are you leaving the connection idle? SQL typically has
> > >> connection timeouts built in so that someone cannot use up all the
> > available
> > >> threads and then dump them without terminating them as a means of
> > denying
> > >> service.
> > >> >
> > >> > When working with SQL I like to open/reconnect, make my queries,
> then
> > >> disconnect right away without any user interaction. Otherwise, a user
> > could
> > >> leave an error dialog open and not respond until after the database
> > times
> > >> out.
> > >> >
> > >> > I usually have in my stack or database connection card scripts for
> > >> initializing and making the connection, idling the connection (which
> is
> > >> really a disconnect) and closing the connection. To SQL this results
> in
> > >> either a connection being made, or else a disconnect, but to my apps
> > after
> > >> the first connection is made, I set a state wherein I know I can
> proceed
> > >> after the first connection is made because I know the database is
> there
> > and
> > >> responding to queries. Hence the "idle state".
> > >> >
> > >> > I wrap all my sql connection/query commands in a try/catch statement
> > so
> > >> that if an error is generated, I call my disconnect handler first,
> then
> > >> alert the user that an error has occurred. This has eliminated
> virtually
> > all
> > >> the normal SQL issues I used to have. It's also good programming
> > practice
> > >> for SQL.
> > >> >
> > >> > Of course, SQLite is a local file (typically) so this is not as much
> > of
> > >> an issue, but still I believe there are default timeouts you can
> > encounter.
> > >> >
> > >> > Also, consider seriously, Trevor DeVore's great SQLYoga utility,
> which
> > >> takes most of the pain and suffering out of working with SQL. You can
> > return
> > >> queries as lists, arrays or records, which I think are a special kind
> of
> > >> SQLYoga array.
> > >> >
> > >> > Bob
> > >> >
> > >> >
> > >> > On May 9, 2011, at 10:26 AM, Maarten Koopmans wrote:
> > >> >
> > >> >> Hi,
> > >> >>
> > >> >> I have a simple "select * from table" against a sqlite dbid in a
> > >> function,
> > >> >> Livecode 4.6.1 on OS 10.6.7
> > >> >>
> > >> >> For some weird reason it errs out, silently. The only reason I can
> > think
> > >> of
> > >> >> is that I didn;t close my cursor in a previous call, but other than
> > >> that, I
> > >> >> am "snow blind". Anybody ever seen this before?
> > >> >>
> > >> >> --Maarten
> > >> >> _______________________________________________
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