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Re: DB API question - where is a stored procedure's return value?

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  Re: DB API question - where is a stored procedure's return value? Petite Abeille <petite.abeille@gmail.com> - 2014-03-13 00:11 +0100
    Re: DB API question - where is a stored procedure's return value? John Gordon <gordon@panix.com> - 2014-03-13 14:43 +0000
      Re: DB API question - where is a stored procedure's return value? Skip Montanaro <skip@pobox.com> - 2014-03-13 10:14 -0500
      Re: DB API question - where is a stored procedure's return value? Chris Angelico <rosuav@gmail.com> - 2014-03-14 04:01 +1100
      Re: DB API question - where is a stored procedure's return value? random832@fastmail.us - 2014-03-13 13:22 -0400
      Re: DB API question - where is a stored procedure's return value? Chris Angelico <rosuav@gmail.com> - 2014-03-14 04:32 +1100

#68311 — Re: DB API question - where is a stored procedure's return value?

On Mar 13, 2014, at 12:00 AM, Ian Kelly <ian.g.kelly@gmail.com> wrote:

> As a general solution, one might wrap a stored procedure that returns
> a value into a stored procedure that has an output parameter and call
> it with callproc.  Some implementations might include a return value
> in the parameter list anyway.

Alternatively… if it’s really a function… wrap it in a select statement… such as:

select foo() as value from dual

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#68331

In <mailman.8114.1394666303.18130.python-list@python.org> Petite Abeille <petite.abeille@gmail.com> writes:


> Alternatively=85 if it=92s really a function=85 wrap it in a select =
> statement=85 such as:

> select foo() as value from dual

That will get the return value into an SQL variable, but the OP wanted
to know how to fetch it from python code.

-- 
John Gordon         Imagine what it must be like for a real medical doctor to
gordon@panix.com    watch 'House', or a real serial killer to watch 'Dexter'.

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#68333

Thanks for the responses. We eventually figured out there appears to
be a bug in the latest version of the python-sybase module (at least
in 0.40, probably in 0.39 as well). It was actually detecting
CS_STATUS_RESULT coming from the server and responding appropriately,
however it was assigning the actual status result to a local variable
instead of an attribute of the Cursor instance. Testing a fix now.

Skip

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#68335

On Fri, Mar 14, 2014 at 1:43 AM, John Gordon <gordon@panix.com> wrote:
>> select foo() as value from dual
>
> That will get the return value into an SQL variable, but the OP wanted
> to know how to fetch it from python code.

In theory, that should produce a one-row-one-column SELECT result,
which can then be retrieved as such. (I say "in theory" because not
all back-end databases support the "from dual" notation - which, by
the way, I find extremely odd; what's 'dual' about it?)

ChrisA

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#68336

On Thu, Mar 13, 2014, at 13:01, Chris Angelico wrote:
> On Fri, Mar 14, 2014 at 1:43 AM, John Gordon <gordon@panix.com> wrote:
> >> select foo() as value from dual
> >
> > That will get the return value into an SQL variable, but the OP wanted
> > to know how to fetch it from python code.
> 
> In theory, that should produce a one-row-one-column SELECT result,
> which can then be retrieved as such. (I say "in theory" because not
> all back-end databases support the "from dual" notation - which, by
> the way, I find extremely odd; what's 'dual' about it?)

DUAL is an Oracle thing. It used to have two rows, in order to be used
to duplicate results by doing a cartesian join to it. At some point,
that was removed, but the name stuck.

Most other servers allow SELECT without FROM.

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#68338

On Fri, Mar 14, 2014 at 4:22 AM,  <random832@fastmail.us> wrote:
> DUAL is an Oracle thing. It used to have two rows, in order to be used
> to duplicate results by doing a cartesian join to it. At some point,
> that was removed, but the name stuck.
>
> Most other servers allow SELECT without FROM.

Yeah, I usually use PostgreSQL which does. I don't remember what DB2
has. MySQL I think requires either DUAL or an actual real table.

ChrisA

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