My idea for using this would be to pair the [sql_query] directly to
the [sqlite] object, then the rest of the time, the data would be in
the form of Pd messages. I think for most people, they'll want to
work in Pd messages as much as possible, then at the last possible
moment, the Pd messages should be converted into SQL queries.
Also, since Pd objects visually represent instances, I think that the
[sqlite] server object should represent one database. If there are
numerous [sqlite] objects representing the same database, then I
think things will get confusing to the Pd user and in the C code. We
tried this in hidio, and it turned out to be a pain. I am not sure
if this is what you are proposing, though, but that is my
understanding of it.
I'll take a look at your design once its out there.
.hc
On Dec 26, 2007, at 10:28 AM, Mike McGonagle wrote:
Hans,
From looking at this (I didn't compile the external yet), but my
first thought about your patch is that it would be very cumbersome
to have the result sets coming out of the "server" object. They
should be coming out of the "query" object, as that is the object
that is handling that particular result set. I kind of envision
that once someone has finished with creating the SQL queries, that
they would then create the processing code to handle each query.
That is something that is specific to the query, and not the
"server" object. The way that you have this, we would still need to
create a separate "query" and "server" object for each query. That
would make swapping the "server" object in and out very difficult,
as it would require replacing ALL of the "server" objects for each
query.Just to let you know, I need to clean up some more stuff, but I
will post my latest version of the "server" and "query" objects
tomorrow. I have not done a whole lot of testing, but I am able to
insert SQL and make the queries, and get results out. It also
handles errors and most recent insert row id stuff...Mike
On Dec 22, 2007 1:27 AM, Hans-Christoph Steiner hans@eds.org wrote:
I just committed my first stabs at a sketch for the [sql_query]
object. It doesn't do anything yet, but it does recognize ?
placeholders as object arguments and creates inlets. Other than
that, the only thing it currently does is crash :).http://pure-data.cvs.sourceforge.net/pure-data/externals/hcs/ sql_query-help.pd http://pure-data.cvs.sourceforge.net/pure-data/externals/hcs/ sql_query.c
.hc
On Dec 21, 2007, at 1:36 PM, Mike McGonagle wrote:
On 12/21/07, Mathieu Bouchard matju@artengine.ca wrote: On Tue, 18 Dec 2007, Mike McGonagle wrote:
[query <srv_id> insert into mytable (id, name, token) values (?
f,'?s','?s')]
In this example, the first placeholder would expect a Float,
with the next
two expecting a Symbol (just think of this as a variation on the
printf
string substitutions).
It looks more like the types of [t] [pack] [unpack] [expr] etc.
Yes, they are PD types.
You don't really need to type your data. SQL is largely typeless:
at least at the level of what you can put in one table cell, anything is a
string. It becomes typed (but auto-cast) when put in the cell, but rebecomes untyped when taken out of the cell.Yes, I know that these things can be stored in a typeless manner,
but the functions that bind the SQL statement with their
placeholders can be of any type, as there are functions for the
various datatypes.http://www.sqlite.org/c3ref/bind_blob.html
This link shows all the different functions used to bind the data
to the statement placeholders.http://dev.mysql.com/doc/refman/5.0/en/c-api-prepared-statement- datatypes.html
And if you look at how MySQL does this, while they only provide a
single bind function, it does have the datatypes for the data in a
structure that gets passed into the bind function.Also, from looking at libdbi, it appears that they don't even
bother with placeholders at all.This is not an issue of how the user sees these things, it is how
the C code interfaces with the database.So, just how do we do this in a consistent manner when all the
different interfaces don't support these things, AND if they do,
they do them differently.but considering that the databases need to know the specific
data types
for each placeholder,
heh? do they?
SQLite does. MySQL appears to as well. And yes, it is possible to
just force everything to be a string/c-string and be done with it.
SQLite actually stores everything as a string anyway, despite the
defined types in the create statement.Mike
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