[storm] using odbc as a backend

[Vernon Cole]

Indeed, this is, IMHO, the biggest sticky problem with ADO and/or odbc
integration.  Taking care of the database specific stuff is exactly what
odbc DOES NOT do. The code we are working on now is specific to using odbc
or ADO to access a Microsoft SQL database.  If some poor unfortunate user
were to try using the same code to get to (for example) an ACCESS database,
things would mysteriously start to break.
  And what happens if we DO open a postgress or MySQL database using ADO?
The code which already knows how to handle those database will not be
called!
  The storm.database.register_scheme(scheme, factory) design is simply not
capable of handeling the complexities involved in a user (or programmer)
friendly way.  The idea that each scheme uses a single specific api
implementation to get to a single specific database server engine will not
hold up in the real world. For example, if I access a MS-SQL database using
adodbapi, I use qmark parameter substitution. To get to the same database
using the Linux odbc driver, I must switch to the %s variety of parameters.
Storm would have to know this.
  Am I supposed to (in my python application program) ask which operating
system I am running on in order to use a different scheme? I think we can do
better, but I am not sure how. Perhaps we will need to implement some sort
of environment layer -- sort of like sys.path() -- in order to smooth this
whole mess out.
--
Vernon Cole


On Fri, Mar 6, 2009 at 2:11 PM, James Henstridge <james at jamesh.id.au> wrote:

> On Fri, Mar 6, 2009 at 3:36 PM, Martin DeMello <martindemello at gmail.com>
> wrote:
> > On Sat, Mar 7, 2009 at 1:09 AM, James Henstridge <james at jamesh.id.au>
> wrote:
> >>
> >> Note that there is database specific code for all three currently
> >> supported databases, so it is very unlikely that a new backend could
> >> be done without similar work.
> >>
> >> This also means that a generic "pyodbc" backend is not on the cards:
> >> it would depend on what database is actually being talked to.
> >>
> >> It probably wouldn't be a huge effort to support PostgreSQL or MySQL
> >> through pyodbc, but I'd guess that isn't what Martin is after.
> >
> > I was hoping that the various database's ODBC drivers would take care
> > of the database-specific stuff, and allow storm to access a common
> > API, as long as I didn't want to do anything too funky (just need
> > simple inserts, selects, updates and deletes, for the most part).
>
> I suppose the most important thing Storm does in the database specific
> code is retrieving automatically assigned primary keys for newly
> inserted rows in the database.  This is something that even the
> simplest Storm apps tend to rely on, so needs to be handled correctly.
>
> There are a few other bits and pieces, but that is the most important one.
>
> James.
>
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