import sqlalchemy
sqlalchemy.create_engine("mssql://myuser:mypwd@my.db.server:1433/mydb?driver=FreeTDS& odbc_options='TDS_Version=8.0'").connect()
The error message for above is:
DBAPIError: (Error) ('08001', '[08001] [unixODBC][FreeTDS][SQL Server]Unable to connect to data source (0) (SQLDriverConnectW)') None None
Can someone please point me in the right direction? Is there a way I can simply tell sqlalchemy to pass a specific connect string through to pyodbc?
Please Note: I want to keep this DSN-less.
The example by @Singletoned would not work for me with SQLAlchemy 0.7.2. From the SQLAlchemy docs for connecting to SQL Server:
If you require a connection string that is outside the options presented above, use the odbc_connect keyword to pass in a urlencoded connection string. What gets passed in will be urldecoded and passed directly.
So to make it work I used:
import urllib
quoted = urllib.quote_plus('DRIVER={FreeTDS};Server=my.db.server;Database=mydb;UID=myuser;PWD=mypwd;TDS_Version=8.0;Port=1433;')
sqlalchemy.create_engine('mssql+pyodbc:///?odbc_connect={}'.format(quoted))
This should apply to Sybase as well.
NOTE: In python 3 the urllib module has been split into parts and renamed. Thus, this line in python 2.7:
quoted = urllib.quote_plus
has to be changed to this line in python3:
quoted = urllib.parse.quote_plus
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I'm still interested in a way to do this in one line within the sqlalchemy create_engine statement, but I found the following workaround detailed here:
import pyodbc, sqlalchemy
def connect():
pyodbc.connect('DRIVER={FreeTDS};Server=my.db.server;Database=mydb;UID=myuser;PWD=mypwd;TDS_Version=8.0;Port=1433;')
sqlalchemy.create_engine('mssql://', creator=connect)
UPDATE: Addresses a concern I raised in my own comment about not being able to pass arguments to the connect string. The following is a general solution if you need to dynamically connect to different databases at runtime. I only pass the database name as a parameter, but additional parameters could easily be used as needed:
import pyodbc
import os
class Creator:
def __init__(self, db_name='MyDB'):
"""Initialization procedure to receive the database name"""
self.db_name = db_name
def __call__(self):
"""Defines a custom creator to be passed to sqlalchemy.create_engine
http://stackoverflow.com/questions/111234/what-is-a-callable-in-python#111255"""
if os.name == 'posix':
return pyodbc.connect('DRIVER={FreeTDS};'
'Server=my.db.server;'
'Database=%s;'
'UID=myuser;'
'PWD=mypassword;'
'TDS_Version=8.0;'
'Port=1433;' % self.db_name)
elif os.name == 'nt':
# use development environment
return pyodbc.connect('DRIVER={SQL Server};'
'Server=127.0.0.1;'
'Database=%s_Dev;'
'UID=user;'
'PWD=;'
'Trusted_Connection=Yes;'
'Port=1433;' % self.db_name)
def en(db_name):
"""Returns a sql_alchemy engine"""
return sqlalchemy.create_engine('mssql://', creator=Creator(db_name))
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import sqlalchemy
sqlalchemy.create_engine("DRIVER={FreeTDS};Server=my.db.server;Database=mydb;UID=myuser;PWD=mypwd;TDS_Version=8.0;Port=1433;").connect()
In that format, SQLAlchemy just ignores the connection string and passes it straight on to pyodbc.
Update:
Sorry, I forgot that the uri has to be url-encoded, therefore, the following works:
import sqlalchemy
sqlalchemy.create_engine("DRIVER%3D%7BFreeTDS%7D%3BServer%3Dmy.db.server%3BDatabase%3Dmydb%3BUID%3Dmyuser%3BPWD%3Dmypwd%3BTDS_Version%3D8.0%3BPort%3D1433%3B").connect()
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Internally "my.db.server:1433" is passed as part of a connection string like SERVER=my.db.server:1433;.
Unfortunately unixODBC/FreeTDS won't accept a port in the SERVER bit. Instead it wants SERVER=my.db.server;PORT=1433;
To use the sqlalchemy syntax for a connection string, you must specify the port as a parameter.
sqlalchemy.create_engine("mssql://myuser:mypwd@my.db.server:1433/mydb?driver=FreeTDS& odbc_options='TDS_Version=8.0'").connect()
becomes:
sqlalchemy.create_engine("mssql://myuser:mypwd@my.db.server/mydb?driver=FreeTDS&port=1433& odbc_options='TDS_Version=8.0'").connect()
To pass various parameters to your connect function, it sounds like format string might do what you want:
def connect(server, dbname, user, pass):
pyodbc.connect('DRIVER={FreeTDS};Server=%s;Database=%s;UID=%s;PWD=%s;TDS_Version=8.0;Port=1433;' % (server, dbname, user, pass))
And you would then call it with something like:
connect('myserver', 'mydatabase', 'myuser', 'mypass')
More info on format strings is here: http://docs.python.org/library/string.html#formatstrings
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