adodbapi and output parameters in stored procedures

[leesquare]

Hello,

I need some help getting output values from my stored procedures when
using adodbapi. There's an example
testVariableReturningStoredProcedure in adodbapitest.py, and that
works for my system. But my stored procedure also inserts and
accesses a table in the database. Here's what I have it boiled down
to:

So, when I have
CREATE PROCEDURE sp_DeleteMeOnlyForTesting
@theInput varchar(50),
@theOtherInput varchar(50),
@theOutput varchar(100) OUTPUT
AS
SET @theOutput=@theInput+@theOtherInput

Then, I can run in python:[u'hello', u'bye', u'hellobye']


If I redefined the procedure as
CREATE PROCEDURE sp_DeleteMeOnlyForTesting
@theInput varchar(50),
@theOtherInput varchar(50),
@theOutput varchar(100) OUTPUT
AS
SELECT * From dbo.testtable
SET @theOutput=@theInput+@theOtherInput

Then, the python comes out as :[u'hello', u'bye', u'']

My search on the web found a couple of posts with similar problems,
but no solutions. I am using SQLOLEDB.1 as Provider, connecting to
SQL Server 2005.

Any help appreciated. I just need one method of passing an output
parameter back to python.

Thanks,
Li

 

[M.-A. Lemburg]

Hello,

I need some help getting output values from my stored procedures when
using adodbapi. There's an example
testVariableReturningStoredProcedure in adodbapitest.py, and that
works for my system. But my stored procedure also inserts and
accesses a table in the database. Here's what I have it boiled down
to:

So, when I have
CREATE PROCEDURE sp_DeleteMeOnlyForTesting
@theInput varchar(50),
@theOtherInput varchar(50),
@theOutput varchar(100) OUTPUT
AS
SET @theOutput=@theInput+@theOtherInput

Then, I can run in python:[u'hello', u'bye', u'hellobye']


If I redefined the procedure as
CREATE PROCEDURE sp_DeleteMeOnlyForTesting
@theInput varchar(50),
@theOtherInput varchar(50),
@theOutput varchar(100) OUTPUT
AS
SELECT * From dbo.testtable
SET @theOutput=@theInput+@theOtherInput

Then, the python comes out as :[u'hello', u'bye', u'']

My search on the web found a couple of posts with similar problems,
but no solutions. I am using SQLOLEDB.1 as Provider, connecting to
SQL Server 2005.

Any help appreciated. I just need one method of passing an output
parameter back to python.

Note that if you can, you should try to avoid output parameters
in stored procedures.

It's much more efficient to use multiple result sets for these,
so instead of doing

SELECT * From dbo.testtable
SET @theOutput=@theInput+@theOtherInput

you would write

SELECT * From dbo.testtable
SELECT @theInput+@theOtherInput

and then fetch the data using:

cursor.callproc(...)
test_table_result_set = cursor.fetchall()
cursor.nextset()
(output_variables,) = cursor.fetchone()

I don't know whether the above works for adodbapi. It does for mxODBC
and most other DB-API compatible modules that support .nextset().

--
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source (#1, Nov 07 2008)________________________________________________________________________

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::


eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
Registered at Amtsgericht Duesseldorf: HRB 46611

 

[leesquare]

Thanks for that excellent pointer!

I was able to do just what you said with

But if my procedure has an insert statement in its midst, it doesn't
work. The cursor.fetchall() gets an exception.
Any ideas?

--Li

 

[Roger Upole]

Hello,

I need some help getting output values from my stored procedures when
using adodbapi. There's an example
testVariableReturningStoredProcedure in adodbapitest.py, and that
works for my system. But my stored procedure also inserts and
accesses a table in the database. Here's what I have it boiled down
to:

So, when I have
CREATE PROCEDURE sp_DeleteMeOnlyForTesting
@theInput varchar(50),
@theOtherInput varchar(50),
@theOutput varchar(100) OUTPUT
AS
SET @theOutput=@theInput+@theOtherInput

Then, I can run in python:[u'hello', u'bye', u'hellobye']


If I redefined the procedure as
CREATE PROCEDURE sp_DeleteMeOnlyForTesting
@theInput varchar(50),
@theOtherInput varchar(50),
@theOutput varchar(100) OUTPUT
AS
SELECT * From dbo.testtable
SET @theOutput=@theInput+@theOtherInput

Then, the python comes out as :[u'hello', u'bye', u'']

My search on the web found a couple of posts with similar problems,
but no solutions. I am using SQLOLEDB.1 as Provider, connecting to
SQL Server 2005.

Any help appreciated. I just need one method of passing an output
parameter back to python.

Thanks,
Li

Output parameters aren't actually retrieved until you've iterated
thru all record sets. The below works using ADO objects
directly, not sure how it would translate into adodbapi.

import win32com.client

conn_str="Driver={SQL Server};Server=.\\SqlExpress;Trusted_Connection=yes;"
sp_name="sp_DeleteMeOnlyForTesting"

c=win32com.client.gencache.EnsureDispatch('adodb.connection',0)
c.Open(conn_str)

cmd=win32com.client.Dispatch('ADODB.Command')
cmd.ActiveConnection=c
cmd.CommandType = win32com.client.constants.adCmdStoredProc
cmd.CommandText = sp_name

cmd.Parameters('@theInput').Value = 'bork'
cmd.Parameters('@theOtherInput').Value = 'borkbork'
rs, rc = cmd.Execute()
rs.NextRecordset()
print (cmd.Parameters('@theOutput').Value)

If the NextRecordset line is commented out, the output parm
is None.

Roger

 

[M.-A. Lemburg]

Thanks for that excellent pointer!

I was able to do just what you said with

But if my procedure has an insert statement in its midst, it doesn't
work. The cursor.fetchall() gets an exception.
Any ideas?

Try this (I haven't checked that it works, but it's a possibility),
assuming your query uses the order SELECT, INSERT, SELECT:

# Fetch results from first SELECT
test_table_result_set = cursor.fetchall()
cursor.nextset()

# Ignore "empty" result set
cursor.nextset()

# Fetch results from second SELECT
(output_variables,) = cursor.fetchone()

--
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source (#1, Nov 08 2008)________________________________________________________________________

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::


eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
Registered at Amtsgericht Duesseldorf: HRB 46611