getting results from IBM DB2 stored procedure

[DeltaFox0018]

Please first make sure you have looked at:

• Documentation: https://github.com/mkleehammer/pyodbc/wiki
• Other issues

Environment

To diagnose, we usually need to know the following, including version numbers. On Windows, be
sure to specify 32-bit Python or 64-bit:

• Python: 3.12.6
• pyodbc: 5.10
• OS: MacOS 15.0.1 (M1 Pro)
• DB: IBM DB2 (IBM Power 9)
• driver: IBM i Access ODBC Driver

Issue

I have a procedure with 3 parameters, 2 input and 1 output.

From DBeaver if I call the procedure as follows CALL my_procedure('user','psw', ?)

I have an output of the following type

Through pyodbc I configured the connection to the DB and ran the same call

`
cnxn = pyodbc.connect("DRIVER=IBM i Access ODBC Driver;SYSTEM=MYIP;UID=USER;PWD=PSW;")

cursor = cnxn.cursor()

# Parameters for the stored procedure
params = ('user', "psw", 0)

cursor.execute("{CALL my_procedure (?, ?, ?)}", params)
print(cursor.fetchall())

`

Running the print either you fetchall, fetchone or fetchval or the following error

Traceback (most recent call last): File "/Users/alessandrovolpato/Desktop/rapportini-backend/main.py", line 43, in <module> print(cursor.fetchone()) ^^^^^^^^^^^^^^^^^ pyodbc.ProgrammingError: No results. Previous SQL was not a query.

Do you know how I can retrieve the output of the procedure?

[gordthompson]

You might try this:

cursor.execute(sql)
try:
    rows = cursor.fetchall()
except pyodbc.ProgrammingError:
    cursor.nextset()
    rows = cursor.fetchall()
print(rows)

[DeltaFox0018]

I have tried but the error is the same

[gordthompson]

A more robust approach would be

cursor.execute(sql)
rows = []
fetching = True
while fetching:
    try:
        rows = cursor.fetchall()
        fetching = False
    except pyodbc.ProgrammingError:
        fetching = cursor.nextset()
print(rows)

[kadler]

pyodbc doesn't support output parameters. There's a workaround documented here

[kadler]

FYI you would need to do something a little different on Db2 since you cannot just declare a variable and you also cannot execute multiple statements as a script:

# Sample procedure
conn.execute("""
create or replace procedure kadler.test_outparm(x out varchar(10))
begin
    set x = 'hello';
end
""")

# Unfortunately, QTEMP not allowed for variables
conn.execute("create variable kadler.test_outparm_out varchar(10)");

# Call the procedure, output goes to the variable created earlier
conn.execute("call kadler.test_outparm(kadler.test_outparm_out)")

# Get the output
output = conn.execute("values(kadler.test_outparm_out)").fetchval()

It's a bit fiddly, but this is the best workaround that I know of. Another alternative would be to replace/wrap the procedure with an SQL scalar function, but that only works if you have a single output parameter and don't need to return any cursors.

[kadler]

An example of the scalar function wrapper for this case might be:

create function my_function(user varchar(10), pass varchar(128))
returns varchar(10) modifies sql data
begin
   declare output varchar(10);
   call my_procedure(user, pass, output);
   return output;
end

Then you'd call it like so:

output = conn.execute("values(my_function(?, ?))", ('user', 'psw')).fetchval()