I can connect via pyODBC to an unsupported database over ODBC. Queries appear to execute correctly. If I try to connect using mssql+pyodbc, I can't connect properly (image not found).
I've tried "base:///", "base+pyodbc:///", or "pyodbc:///".
Do I need to write my own "dialect" that doesn't make any changes to base, and are there any useful (up to date) guides on how to do this?
EDIT:
import pyodbc
conn = pyodbc.connect(DSN = "ODBCCONNECTIONNAME", UID = "ODBCUSER", PWD="PASSWORD")
cursor = conn.cursor()
Also works with this line replacing the connection above:
conn = pyodbc.connect("DSN=fmp_production;UID=odbc_user;PWD=Pwd222")
I can then run selects, and modifications fine, using standard SQL.
EDIT:
Okay, so I'm getting an error:
"Abort trap: 6" basically my python process is crashing out. I've tried testing with a functioning ODBC connection to a MySQL database, using:
engine = create_engine('mysql+pyodbc://root:rootpwd#testenvironment')
If I include the name of the database, then I get an image not found error instead. But I think the actual problem is whatever is crashing my python.
Related
I am trying to pull a query using pyodbc and it keeps returning a reset by peer error, I can run the query no issue 100% of the time in Teradata SQL Assistant.
This happens with one other query I use but everything else I have done works using the same code.
I have tried running it multiple times, always works in Teradata SQL Assistant but not in python. Hundreds of other queries have worked with no issue, only two have given issues. I have tried slightly changing the queries with no luck.
I also tried in R with RODBC and it worked there.
I asked our DBA team and they said they have no process that would automatically boot that process and there is no issues with the query.
import pyodbc
import pandas.io.sql as psql
connection_info = 'DSN=xxxxxx'
conn = pyodbc.connect(connection_info)
sql1 = '''
QUERY HERE
'''
df = psql.read_sql_query(sql1, conn)
expect df to = resuls, instead get the following error:
10054 WSA E ConnReset: Connection reset by peer
I am using sqlalchemy to connect to MySQL database and found a strange behavior.
If I query
LOAD DATA LOCAL INFILE
'C:\\\\Temp\\\\JaydenW\\\\iata_processing\\\\icer\\\\rename\\\\ICER_2017-10-
12T09033
7Z023870.csv
It pops an error:
sqlalchemy.exc.InternalError: (pymysql.err.InternalError) (1148, u'The used
command is not allowed with this MySQL versi
on') [SQL: u"LOAD DATA LOCAL INFILE
'C:\\\\Temp\\\\JaydenW\\\\iata_processing\\\\icer\\\\rename\\\\ICER_2017-10-
12T090337Z023870.csv' INTO TABLE genie_etl.iata_icer_etl LINES TERMINATED BY
'\\n'
IGNORE 1 Lines (rtxt);"] (Background on this error at:
http://sqlalche.me/e/2j85)
And I find the reason is that:
I need to set the parameter as
args = "mysql+pymysql://"+username+":"+password+"#"+hostname+"/"+database+"?
local_infile=1"
If I use MySQL official connection library. I do not need to do so.
myConnection = MySQLdb.connect(host=hostname, user=username, passwd=password, db=database)
Can anyone help me to understand the difference between the two mechanisms?
The reason is that the mechanisms use different drivers.
In SQLAlchemy you appear to be using the pymysql engine, which uses the PyMySQL Connection class to create the DB connection. That one requires the user to explicitly pass the local_infile parameter if they want to use the LOAD DATA LOCAL command.
The other example uses MySQLdb, which is basically a wrapper around the MySQL C API (and to my knowledge not the official connection library; that would be MySQL Connector Python, which is also available on SQLAlchemy as mysqlconnector). This one apparently creates the connection in a way that the LOAD DATA LOCAL is enabled by default.
I am using pyodbc to connect to an azure sql database. My source code looks like this:
import pyodbc
server = 'sqlserver.database.windows.net'
database = 'database'
username = 'username'
password = 'password'
conn= pyodbc.connect('DRIVER={ODBC Driver 13 for SQL Server}'+';SERVER='+server+';PORT=1443;DATABASE='+database+';UID='+username+';PWD='+ password ';Encrypt=yes;TrustServerCertificate=no;Connection Timeout=30;')
cursor = conn.cursor()
cursor.execute("query")
I am able to connect to a sql database. The only thing which is not working properly is that pyodbc does not connect to the database I have specified in the database variable. It always connects to the master database.
What I have tried so far is to print the name of the databases on the target sql server using SELECT * FROM sys.databases while being connected to the master database. I was able to see the database I am trying to connect to. Anyone got an idea what goes wrong in my source code?
In general, I would assume that the connection string needs to be different in your case.
As per pyodbc docs:
[...]the most important thing to remember is that pyodbc does not even look at the connection string. It is passed directly to the database driver unmodified (through SQLDriverConnect). Connection strings are therefore driver-specific and all ODBC connection string documentation should be valid.
https://github.com/mkleehammer/pyodbc/wiki/Connecting-to-databases
However, since you are connecting to db OK and your connection string seems to be ignored, I would say that if you are using Windows then the connection parameters seem likely to be defined in the ODBC DSN, which can be changed in Control panel. If that is the case, and you have ODBC parameters defined in DSN, most likely your connection string is ignored, except for the choice of the DSN.
I have a daemon that uses sqlalchemy to interact with MySQL database. Since interaction is seldom, the connections are prone to timing out. I've tried to fix the problem by setting various flags when creating the database engine, e.g. pool_recycle=3600, but nothing seems to help.
To help me debug the problem, I set the timeout of my local mysql server to 10 seconds, and tried the following program.
import time
import sqlalchemy
engine = sqlalchemy.engine.create_engine("mysql://localhost")
while True:
connection = engine.connect()
result = connection.execute("SELECT 1")
print result.fetchone()
connection.close()
time.sleep(15)
Surprisingly, I continue to get exceptions like the following:
sqlalchemy.exc.OperationalError: (OperationalError) (2006, 'MySQL server has gone away')
However, if I remove the call to connection.close(), the problem goes away. What is going on here? Why isn't sqlalchemy trying to establish a new connection each time I call connect()?
I'm using Python 2.7.3 with sqlalchemy 0.9.8 and MySQL 5.5.40.
the document mention:
MySQL features an automatic connection close behavior,
for connections that have been idle for eight hours or more.
To circumvent having this issue, use the pool_recycle option
which controls the maximum age of any connection:
engine = create_engine('mysql+mysqldb://...', pool_recycle=3600)
You can just put "pool_recycle" parameter when the create_engine is invoked.
I'm not 100% sure if this is going to fix your problem or not, but I ran into a similar issue when dealing with mysql. It was only fixed when I used pymysql to connect to the database.
You can install like this:
pip install pymysql
Which will work for both linux and windows (if you have it installed)
Then give your connection string like this:
import time
import sqlalchemy
engine = sqlalchemy.engine.create_engine("mysql+pymysql://localhost")
while True:
connection = engine.connect()
result = connection.execute("SELECT 1")
print result.fetchone()
connection.close()
time.sleep(15)
I get the following output when I run it:
(1,)
(1,)
(1,)
(1,)
On another note, I have found certain queries to break with SQLAlchemy 0.9.8. I had to install version 0.9.3 in order for my applications to not break anymore.
I'm attempting to connect to a SQL Server instance from a Windows box using pymssql (version 2.0.0b1-dev-20111019 with Python 2.7.1). I've tried the most basic approach from the console:
import pymssql
c = pymssql.connect(host = r'servername\instance',
user = 'username',
password = 'userpassword')
In response to this, I get the very helpful error: InterfaceError: Connection to the database failed for an unknown reason.
I am reasonably confident that the connection information is correct, as it works when I use adodbapi, with the following commands:
import adodbapi
c = adodbapi.connect(r'Provider=sqloledb;Data Source=servername\instance;User ID=username;password=userpassword;'
c.close
I've tried adding the port number to the host parameter, with the same result. Does anyone have a suggestion on how to go about resolving this issue?
Incidentally, I've read the responses at "Unable to connect to SQL Server via pymssql". The OP eventually resolved his issue by correctly configuring FreeTDS, which, from what I can tell, is not used by pymssql on Windows.
Based on #cha0site's recommendation, I have tried using just the hostname, rather than the hostname and instance. This resulted in the same error, but it seemed to take longer to generate the error (though the traceback still indicates the same line). The reason I have been specifying the instance is that I was not able to connect using SSMS unless I specified the instance, so I assumed that it would be necessary for other connections.
I've now also tried pymssql.connect(host='servername', user='username', password='userpassword', database='instance') with the same result (based on #Sid's comment). Based on the pymssql documentation, I believe the database parameter is used to specify the initial database that the user is to be connected to, rather than the instance.
Just to clarify, "instance" is the name provided during installation of SQL Server, not a database within that installation. It occurs to me that it's possible that pymssql does not support this notation, so I will look into re-configuring the SQL Server instance so that it is not required.
I've now re-installed SQL Server as a default instance, rather than a named instance, which allows me to connect without specifying the instance name. adodbapi still works (without /instance), but pymssql still returns the same error. I've also removed and re-installed pymssql from a freshly downloaded archive (still the same version).
Check your freetds.conf file and see if you have set the port 1219., then check again the connexion:
DB = pymssql.connect(host='DB',user='youruser',password='yourpwd',database='yourDBname')
Edit: example of my freetds.conf file Python:
host = 'IP'
port = 1219
To specify host=servername\instance or server=servername\instance, the SQL Server Browser service must be on the SQL Server machine.