How do I access AS/400 using SQLAlchemy?

Question

Short version: Please tell me how to connect to AS/400s via SQLAlchemy.

Long version

My ultimate goal is to join data from SQL Server and AS/400 to be displayed in a Flask Python application. My approach has been to get the data from each database into Pandas dataframes, which can then be joined and output as JSON. If anyone has a better approach, feel free to leave a comment. The problem with the way I'm trying to do this is that Pandas.read_sql_query() relies on SQLAlchemy, and getting SQLAlchemy to work with AS/400 is proving quite difficult.

• The AS/400 is version 7.2, though another I will likely try to connect to is version 5.1.
• I'm trying to access it from my computer, which is running Windows 7 and has i Access 7.1, Python 2.7, and Python modules including pyodbc and ibm_db_sa .

Without sqlalchemy , pyodbc works just fine:

CONNECTION_STRING = (
    "driver={iSeries Access ODBC Driver};"
    "system=ip_address;"
    "database=database_name;"
    "uid=username;"
    "pwd=password;"
) 
pyodbc.connect(CONNECTION_STRING)
# Queries work fine after this.

I've read these resources, among others, and tried to apply their techniques:

• https://pypi.org/project/ibm_db_sa/
• Connecting to IBM AS400 server for database operations hangs
• SqlAlchemy equivalent of pyodbc connect string using FreeTDS

Below are some of the failed attempts and corresponding error messages that I've collected. I don't know what to put for the first part (" something+something//... "), which port to specify (446? 8471? something else? nothing?), whether to use the server's name or IP address, or whether to use the connection-string style argument for create_engine() , so I've just been trying every combination I can think of. I tried modifying the AS400Dialect_pyodbc class as suggested in the second link above, after which I tried rerunning some of the failed attempts again. I may keep trying things, but I'm just spinning my wheels at this point.

from sqlalchemy import create_engine

CONNECTION_STRING = (
    "driver={iSeries Access ODBC Driver};"
    "system=ip_address;"
    "database=database_name;"
    "uid=username;"
    "pwd=password;"
)

create_engine('ibm_db_sa+pyodbc://username:password@ip_address:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.InterfaceError (pyodbc.InterfaceError) ('IM002', u'[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)') (Background on this error at: http://sqlalche.me/e/rvf5 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 43, in

create_engine('ibm_db_sa://username:password@ip_address:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL30061N The database alias or database name "database_name " was not found at the remote node. SQLSTATE=08004\\r SQLCODE=-30061 (Background on this error at: http://sqlalche.me/e/e3q8 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 43, in

create_engine('ibm_db_sa://username:password@server_name:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL1336N The remote host "server_name" was not found. SQLSTATE=08001\\r SQLCODE=-1336 (Background on this error at: http://sqlalche.me/e/e3q8create_engine ('ibm_db_sa://username:password@ip_address:446/server_name.database_name').connect()

create_engine('ibm_db_sa://username:password@ip_address:446/server_name.database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL30061N The database alias or database name "server_name.database_name " was not found at the remote node. SQLSTATE=08004\\r SQLCODE=-30061 (Background on this error at: http://sqlalche.me/e/e3q8 )

create_engine('db2+ibm_db://username:password@ip_address:446/server_name.database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL30061N The database alias or database name "server_name.database_name " was not found at the remote node. SQLSTATE=08004\\r SQLCODE=-30061 (Background on this error at: http://sqlalche.me/e/e3q8 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 45, in

create_engine('db2+ibm_db://username:password@ip_address:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL30061N The database alias or database name "database_name " was not found at the remote node. SQLSTATE=08004\\r SQLCODE=-30061 (Background on this error at: http://sqlalche.me/e/e3q8 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 45, in

create_engine('db2+ibm_db://username:password@ip_address/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL30081N A communication error has been detected. Communication protocol being used: "TCP/IP". Communication API being used: "SOCKETS". Location where the error was detected: "ip_address". Communication function detecting the error: "connect". Protocol specific error code(s): "10061", " ", " ". SQLSTATE=08001\\r SQLCODE=-30081 (Background on this error at: http://sqlalche.me/e/e3q8 )

create_engine('db2+ibm_db://username:password@server_name:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL1336N The remote host "server_name" was not found. SQLSTATE=08001\\r SQLCODE=-1336 (Background on this error at: http://sqlalche.me/e/e3q8 )

create_engine('db2+ibm_db://username:password@server_name/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL1336N The remote host "server_name" was not found. SQLSTATE=08001\\r SQLCODE=-1336 (Background on this error at: http://sqlalche.me/e/e3q8 )

create_engine('db2+pyodbc://username:password@ip_address:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.InterfaceError (pyodbc.InterfaceError) ('IM002', u'[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)') (Background on this error at: http://sqlalche.me/e/rvf5 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 45, in

create_engine('db2://username:password@ip_address:446/database_name').connect()

Exception has occurred: sqlalchemy.exc.OperationalError (ibm_db_dbi.OperationalError) ibm_db_dbi::OperationalError: [IBM][CLI Driver] SQL30061N The database alias or database name "database_name " was not found at the remote node. SQLSTATE=08004\\r SQLCODE=-30061 (Background on this error at: http://sqlalche.me/e/e3q8 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 45, in

quoted = urllib.quote_plus(CONNECTION_STRING)
create_engine('ibm_db_sa+pyodbc:///?odbc_connect={}'.format(quoted)).connect()

Unable to open 'hashtable_class_helper.pxi': File not found (file:///c:/git/dashboards/pandas/_libs/hashtable_class_helper.pxi).

quoted = urllib.quote_plus(CONNECTION_STRING)
create_engine('ibm_db_sa:///?odbc_connect={}'.format(quoted)).connect()

Exception has occurred: sqlalchemy.exc.InterfaceError (ibm_db_dbi.InterfaceError) ibm_db_dbi::InterfaceError: connect expects the first five arguments to be of type string or unicode (Background on this error at: http://sqlalche.me/e/rvf5 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 43, in

quoted = urllib.quote_plus(CONNECTION_STRING)
create_engine('ibm_db:///?odbc_connect={}'.format(quoted)).connect()

Exception has occurred: sqlalchemy.exc.NoSuchModuleError Cant load plugin: sqlalchemy.dialects:ibm_db

quoted = urllib.quote_plus(CONNECTION_STRING)
create_engine('db2:///?odbc_connect={}'.format(quoted)).connect()

Exception has occurred: sqlalchemy.exc.InterfaceError (ibm_db_dbi.InterfaceError) ibm_db_dbi::InterfaceError: connect expects the first five arguments to be of type string or unicode (Background on this error at: http://sqlalche.me/e/rvf5 ) File "C:\\Git\\dashboards\\web_app\\pandas db2 test.py", line 45, in

quoted = urllib.quote_plus(CONNECTION_STRING)
create_engine('db2+ibm_db:///?odbc_connect={}'.format(quoted)).connect()

Exception has occurred: sqlalchemy.exc.InterfaceError (ibm_db_dbi.InterfaceError) ibm_db_dbi::InterfaceError: connect expects the first five arguments to be of type string or unicode (Background on this error at: http://sqlalche.me/e/rvf5 )

quoted = urllib.quote_plus(CONNECTION_STRING)
create_engine('db2+ibm_db_sa:///?odbc_connect={}'.format(quoted)).connect()

Exception has occurred: sqlalchemy.exc.NoSuchModuleError Cant load plugin: sqlalchemy.dialects:db2.ibm_db_sa

Answer 1

I finally got it working, though it's a bit awkward. I created a blank file in my project to appease this message that I was receiving in response to one of the attempts shown in my question:

Unable to open 'hashtable_class_helper.pxi' : File not found ( file:///c:/git/dashboards/pandas/_libs/hashtable_class_helper.pxi ).

(My project folder is C:/Git/dashboards , so I created the rest of the path.)

With that file present, the code below now works for me. engine.connect() works, but I ran an actual query for further verification that it was working. For the record, it seems to work regardless of whether the ibm_db_sa module is modified as suggested in one of the links in my question, so I would recommend leaving that module alone. Note that although they aren't imported by directly, you need these modules installed: pyodbc , ibm_db_sa , and possibly future (I forget).

import urllib
import pandas as pd
from sqlalchemy import create_engine

CONNECTION_STRING = (
    "driver={iSeries Access ODBC Driver};"
    "system=ip_address;"
    "database=database_name;"
    "uid=username;"
    "pwd=password;"
)

SQL= """\
SELECT
    MPBASE AS BASEPA,
    COALESCE(SUM(MPQTY), 0) AS PWIP
FROM FUTMODS.MPPROD
WHERE MPOPT <> '*'
GROUP BY MPBASE
"""

quoted = urllib.quote_plus(CONNECTION_STRING)
engine = create_engine('ibm_db_sa+pyodbc:///?odbc_connect={}'.format(quoted))

df = pd.read_sql_query(
    SQL,
    engine,
    index_col='basepa'
)
print df