[PD-dev] Fwd: Connecting up an SQL Database to PD

[Mike McGonagle]

---------- Forwarded message ----------
From: Mike McGonagle <mjmogo at gmail.com>
Date: Nov 8, 2007 12:35 PM
Subject: Re: [PD-dev] Connecting up an SQL Database to PD
To: Hans-Christoph Steiner <hans at eds.org>


On 11/7/07, Hans-Christoph Steiner <hans at eds.org> wrote:
>
> On Nov 7, 2007, at 4:37 AM, Frank Barknecht wrote:
>
> > Hallo,
> > Hans-Christoph Steiner hat gesagt: // Hans-Christoph Steiner wrote:
> >
> AFAIK, MySQL and the like do not guarantee realtime responses, and
> network connections certainly do not. So if want something that is
> designed to do that, then use [pool], [textfile], or perhaps an
> embedded SQLlite, if it is quick enough.

I have been gone for a couple of days (under a germ...) and during
that time, A LOT has been posted here, and I would like to spend some
time reading the responses...

But, in that down time, I was playing with SQLite, and actually have
an object that can send arbitrary queries, taking input from PD inlets
(both float and symbol). After thinking over how to do this, I
realized that VERY SIMPLE SQL statments can be entered into a PD
objects creation arguments. While not the most elegant, it is very
functional for reading. I know the writing works, but just how fast it
is will have to be determined. (SQLite writes a lot faster when using
transactions, one test I did without transactions, it took almost 2
hours to load 36000 records (each with 10 data elements), with
transactions turned on it was a matter of minutes. (These tests were
not done using the PD interface, but using the commandline version of
SQLite.)

Anyway, on skimming the thread, Ben's idea of working with PD struct
definitions is a really good one. I want to be able to take a
definition for a PD struct, and generate an SQL table based on that. I
was playing with this doing some 'SELECT' statements from my object,
and with a metronome triggering it once every 20ms, it was reading
fairly consistently.

So, that being said, I don't have anyway of sending the data to an
outlet, it just currently dumps all the result sets to the console. As
the amount of data that can be retrieved can be STAGGERING, there
needs to be some reasonable thought given to how to handle the result
sets. I would think that the access is pretty fast that smaller chunks
of data can be read, processed, and then re-read...

I don't know if anyone would be interested in seeing the external that
I have so far (while there are only a couple of files, it is kind of
messy), but the file for SQLite is almost 2.5 megs, just by itself.
Compressed, this whole thing is about 1.2 megs. The compiled external
comes out to be able .5 megs. I am working on PPC 10.4.10 Mac, so
anyone using that could probably use my compiled external. Anyone on
other platforms will have to fend with my simple makefile.

You can get the files from ftp.wpco.com, with the user 'fsr', and the
password of 'puredata'. There is a zip file with the external source,
a makefile, a couple of preliminary examples. Try the 'test2' one, as
it may be the most understandable. Also, as I said, this doesn't
really do much more than spew to the console, but it is a start.

Let me have it!!!


Mike

PS. I am still going to read this whole thread, but that will be a
little later. Thanks again.

>
> Unless there are ways to guarantee the database will reply within one
> clock tick (usually ~1.5ms), then the interface should represent the
> reality of the situation.  Otherwise the database object will cause
> lots of clicks and interruptions when used.
>
> .hc
>
> >
> > Ciao
> > --
> >  Frank Barknecht                                     _
> > ______footils.org__
> >
> > _______________________________________________
> > PD-dev mailing list
> > PD-dev at iem.at
> > http://lists.puredata.info/listinfo/pd-dev
>
>
>
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> ----
>
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"I place economy among the first and most important republican
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To preserve our independence, we must not let our rulers load us with
perpetual debt."
-- Thomas Jefferson, third US president, architect and author (1743-1826)

"Give Peace a Chance" -- John Lennon (9 October 1940 – 8 December 1980)

Peace may sound simple—one beautiful word— but it requires everything
we have, every quality, every strength, every dream, every high ideal.
—Yehudi Menuhin (1916–1999), musician

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—Mark Twain

"Art may imitate life, but life imitates TV."
Ani DiFranco


-- 
Help the Environment, Plant a Bush back in Texas!

"I place economy among the first and most important republican
virtues, and public debt as the greatest of the dangers to be feared.
To preserve our independence, we must not let our rulers load us with
perpetual debt."
-- Thomas Jefferson, third US president, architect and author (1743-1826)

"Give Peace a Chance" -- John Lennon (9 October 1940 – 8 December 1980)

Peace may sound simple—one beautiful word— but it requires everything
we have, every quality, every strength, every dream, every high ideal.
—Yehudi Menuhin (1916–1999), musician

If you think you can, or you think you can't, you are probably right.
—Mark Twain

"Art may imitate life, but life imitates TV."
Ani DiFranco