AW: AW: How to narrow SQL search with multiple criterias?

Tiemo Hollmann TB toolbook at kestner.de
Thu Jan 27 01:48:03 CST 2011


Thanks Bob and Peter, that are valuable thoughts.
Tiemo

> -----Ursprüngliche Nachricht-----
> Von: use-livecode-bounces at lists.runrev.com [mailto:use-livecode-
> bounces at lists.runrev.com] Im Auftrag von Bob Sneidar
> Gesendet: Mittwoch, 26. Januar 2011 19:04
> An: How to use LiveCode
> Betreff: Re: AW: How to narrow SQL search with multiple criterias?
> 
> Also remember that Trevor's sqlYoga has the ability to create query
> objects, and then update those objects and re-run the query. The API
> builds the SQL for you, so it's very easy to do recursive queries.
> 
> As an aside, there is a way in mySQL (and others I am sure) to output
> the query as a new temporary table, assuming you have CREATE TABLE
> rights to the database. This can be a better way to handle large
> datasets.
> 
> For instance, let's say you want the detail for every invoice in the
> prior year sorted by item code, and subtotalled for each item and
> totaled at the end. If the business is a very busy and profitable one,
> that could be a helluvalotta data! (Assume you are CDW for a moment).
> You would never want to return that much data to a memory variable!
> 
> By having the engine output to a temp table you can then run the report
> on that, and never have to worry about overwhelming Rev.
> 
> Bob
> 
> 
> On Jan 26, 2011, at 9:34 AM, Peter Haworth wrote:
> 
> > I think the problem with using LC to narrow down the results of an
> SQL SELECT is that the database may have changed since doing the
> initial SELECT so what you end up with may not reflect the current
> state of the database.  I guess that may not matter to your
> application, or maybe you've locked the database so it can't change but
> definitely a consideration.
> >
> > I've been doing this by saving the contents of the WHERE Clause for
> the SELECT in a variable then appending the additional selection
> criteria to it and issuing a new SELECT statement with the revised
> WHERE clause.
> >
> > Don't have an opinion on the efficiency aspects of LC vs SQL, I
> suspect it depends on a lot of factors.
> >
> > Pete Haworth
> >
> > On Jan 26, 2011, at 8:57 AM, Tiemo Hollmann TB wrote:
> >
> >> Hi William,
> >> That's what I thought, to cycle through the SQL result data with LC,
> but was
> >> unsure how performing it is. I have let's say 20000 records and have
> to
> >> check multiple properties with multiple values. Will the result of
> my cycle
> >> still be so fast, that the user doesn't has to wait for it, because
> it
> >> should just be a nice usability feature to disable the remaining
> selections
> >> and is not necessary for life. I was unsure, if cycling through the
> result
> >> with LC would be state of the art to realize such feature.
> >> Probably I have to code it and make real performance test with and
> without
> >> this feature. Perhaps the SQL Select is so much more time consuming,
> that my
> >> LC cycle isn't relevant anyway.
> >> Thanks
> >> Tiemo
> >>
> >>> -----Ursprüngliche Nachricht-----
> >>> Von: use-livecode-bounces at lists.runrev.com [mailto:use-livecode-
> >>> bounces at lists.runrev.com] Im Auftrag von william humphrey
> >>> Gesendet: Dienstag, 25. Januar 2011 17:55
> >>> An: How to use LiveCode
> >>> Betreff: Re: How to narrow SQL search with multiple criterias?
> >>>
> >>> Sometimes, SQL failure that I am, I just dump it all in a variable
> and
> >>> look
> >>> through it using LiveCode. It depends how big although LiveCode is
> >>> pretty
> >>> quick.
> >>>
> >>
> >>
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