"No driver name specified" writing pandas data frame into SQL Server table
Question:
I am trying to write a Pandas’ DataFrame into an SQL Server table. Here is my example:
import pyodbc
import pandas as pd
import sqlalchemy
df = pd.DataFrame({'MDN': [242342342] })
engine = sqlalchemy.create_engine('mssql://localhost/Sandbox?trusted_connection=yes')
df.to_sql('Test',engine, if_exists = 'append',index = False)
I am getting the following error message. Any thoughts on how to fix?
c:python34libsite-packagessqlalchemyconnectorspyodbc.py:82: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
"No driver name specified; "
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-25-78677a18ce2d> in <module>()
4 engine = sqlalchemy.create_engine('mssql://localhost/Sandbox?trusted_connection=yes')
5
----> 6 df.to_sql('Test',engine, if_exists = 'append',index = False)
7
8 #cnxn.close()
c:python34libsite-packagespandascoregeneric.py in to_sql(self, name, con, flavor, schema, if_exists, index, index_label, chunksize, dtype)
980 self, name, con, flavor=flavor, schema=schema, if_exists=if_exists,
981 index=index, index_label=index_label, chunksize=chunksize,
--> 982 dtype=dtype)
983
984 def to_pickle(self, path):
c:python34libsite-packagespandasiosql.py in to_sql(frame, name, con, flavor, schema, if_exists, index, index_label, chunksize, dtype)
547 pandas_sql.to_sql(frame, name, if_exists=if_exists, index=index,
548 index_label=index_label, schema=schema,
--> 549 chunksize=chunksize, dtype=dtype)
550
551
c:python34libsite-packagespandasiosql.py in to_sql(self, frame, name, if_exists, index, index_label, schema, chunksize, dtype)
1564 if_exists=if_exists, index_label=index_label,
1565 dtype=dtype)
-> 1566 table.create()
1567 table.insert(chunksize)
1568
c:python34libsite-packagespandasiosql.py in create(self)
646
647 def create(self):
--> 648 if self.exists():
649 if self.if_exists == 'fail':
650 raise ValueError("Table '%s' already exists." % self.name)
c:python34libsite-packagespandasiosql.py in exists(self)
634
635 def exists(self):
--> 636 return self.pd_sql.has_table(self.name, self.schema)
637
638 def sql_schema(self):
c:python34libsite-packagespandasiosql.py in has_table(self, name, schema)
1577 query = flavor_map.get(self.flavor)
1578
-> 1579 return len(self.execute(query, [name,]).fetchall()) > 0
1580
1581 def get_table(self, table_name, schema=None):
c:python34libsite-packagespandasiosql.py in execute(self, *args, **kwargs)
1465 cur = self.con
1466 else:
-> 1467 cur = self.con.cursor()
1468 try:
1469 if kwargs:
AttributeError: 'Engine' object has no attribute 'cursor'
Also, is there ways to write connection string for create_engine differently? I would love to write it in form of a dictionary rather than a string.
Update: Here is my new environment:
MS SQL Server: Microsoft SQL Server 2012 – 11.0.2100.60 (X64)
Feb 10 2012 19:39:15
Copyright (c) Microsoft Corporation
Standard Edition (64-bit) on Windows NT 6.2 (Build 9200: )
Python: 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:43:06) [MSC v.1600 32 bit (Intel)]
Pandas version: ‘0.16.2’
sqlalchemy version: 1.1.3
Jupyter server version : 4.2.3
Now the line
engine = sqlalchemy.create_engine('mssql+pyodbc://localhost/Sandbox?trusted_connection=yes')
generates the following error:
c:python34libsite-packagessqlalchemyconnectorspyodbc.py:82: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
"No driver name specified; "
Answers:
The likely problem is that you have not specified the driver, so try:
engine = sqlalchemy.create_engine('mssql+pyodbc://localhost/Sandbox?trusted_connection=yes')
This is based on the warning message that you got on the top:
c:python34libsite-packagessqlalchemyconnectorspyodbc.py:82: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
"No driver name specified; "
Note that you can also use pymssql instead of pyodbc, but MS recommends the latter.
EDIT
Here is official documentation on how to connect with/without DSN (data source name):
https://github.com/mkleehammer/pyodbc/blob/master/docs/index.md#connect-to-a-database
You need to specify both that you want to use ODBC and what ODBC driver to use.
engine = sqlalchemy.create_engine('mssql+pyodbc://localhost/Sandbox?driver=SQL+Server+Native+Client+11.0')
Trusted connections are the default, so you don’t need to specify that, although it shouldn’t hurt to do so.
Update:
2022-02-18: The latest ODBC driver for SQL Server seems to be "ODBC Driver 17 for SQL Server". The driver named "SQL Server" is old and should not be used.
@user1718097 gives the useful suggestion of using [x for x in pyodbc.drivers()] to list the installed drivers.
You can also list the installed drivers with the Get-OdbcDriver cmdlet in powershell.
I know the question has been answered for some time now and it’s just a warning, but if you have transferred everything correctly and this error still occurs it’s annoying.
For all those who had to struggle with it like I did, you can also enter the driver directly in the script, Pyodbc.py offers the possibility for this (row 26 – 28):
# for non-DSN connections, this *may* be used to
# hold the desired driver name
pyodbc_driver_name = 'ODBC Driver 17 for SQL Server'
Above information was much useful. Commenting below version of mine as consolidated which can help freshers during search.
#using library pandas and pyodbc – if not available please use pip install commands to install library based on version. Python version used here is 3.7.8
import pandas as pd
from sqlalchemy import create_engine
import pyodbc
#This query will work for sql authentication
def mssql_engine():
engine = create_engine('mssql+pyodbc://type_username:type_password@type_servername_or_localhostname/type_database_name?driver=SQL+Server+Native+Client+11.0')
return engine
#This query will for windows authentication
#Note: Uncomment below code for windows authentication
#def mssql_engine():
#engine = create_engine('mssql+pyodbc://localhostname/db_name?driver=SQL+Server+Native+Client+11.0')
#return engine
query = 'select * from table_name'
#using pandas to read from sql and passing connection string as function
df = pd.read_sql(query, mssql_engine() )
#printing result
print(df)
I ran into a similar problem with SQLModel with an error message like:
SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections return _create_engine(url, **current_kwargs) # type: ignore
Using @cco ‘s response solved the issue:
CONNECTION_URL = f"mssql+pyodbc://{SQL_SERVER_USERNAME}:{SQL_SERVER_PASSWORD}"
f"@{SQL_SERVER_NAME}/{SQL_SERVER_DATABASE}?driver=SQL%20Server"
I am trying to write a Pandas’ DataFrame into an SQL Server table. Here is my example:
import pyodbc
import pandas as pd
import sqlalchemy
df = pd.DataFrame({'MDN': [242342342] })
engine = sqlalchemy.create_engine('mssql://localhost/Sandbox?trusted_connection=yes')
df.to_sql('Test',engine, if_exists = 'append',index = False)
I am getting the following error message. Any thoughts on how to fix?
c:python34libsite-packagessqlalchemyconnectorspyodbc.py:82: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
"No driver name specified; "
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-25-78677a18ce2d> in <module>()
4 engine = sqlalchemy.create_engine('mssql://localhost/Sandbox?trusted_connection=yes')
5
----> 6 df.to_sql('Test',engine, if_exists = 'append',index = False)
7
8 #cnxn.close()
c:python34libsite-packagespandascoregeneric.py in to_sql(self, name, con, flavor, schema, if_exists, index, index_label, chunksize, dtype)
980 self, name, con, flavor=flavor, schema=schema, if_exists=if_exists,
981 index=index, index_label=index_label, chunksize=chunksize,
--> 982 dtype=dtype)
983
984 def to_pickle(self, path):
c:python34libsite-packagespandasiosql.py in to_sql(frame, name, con, flavor, schema, if_exists, index, index_label, chunksize, dtype)
547 pandas_sql.to_sql(frame, name, if_exists=if_exists, index=index,
548 index_label=index_label, schema=schema,
--> 549 chunksize=chunksize, dtype=dtype)
550
551
c:python34libsite-packagespandasiosql.py in to_sql(self, frame, name, if_exists, index, index_label, schema, chunksize, dtype)
1564 if_exists=if_exists, index_label=index_label,
1565 dtype=dtype)
-> 1566 table.create()
1567 table.insert(chunksize)
1568
c:python34libsite-packagespandasiosql.py in create(self)
646
647 def create(self):
--> 648 if self.exists():
649 if self.if_exists == 'fail':
650 raise ValueError("Table '%s' already exists." % self.name)
c:python34libsite-packagespandasiosql.py in exists(self)
634
635 def exists(self):
--> 636 return self.pd_sql.has_table(self.name, self.schema)
637
638 def sql_schema(self):
c:python34libsite-packagespandasiosql.py in has_table(self, name, schema)
1577 query = flavor_map.get(self.flavor)
1578
-> 1579 return len(self.execute(query, [name,]).fetchall()) > 0
1580
1581 def get_table(self, table_name, schema=None):
c:python34libsite-packagespandasiosql.py in execute(self, *args, **kwargs)
1465 cur = self.con
1466 else:
-> 1467 cur = self.con.cursor()
1468 try:
1469 if kwargs:
AttributeError: 'Engine' object has no attribute 'cursor'
Also, is there ways to write connection string for create_engine differently? I would love to write it in form of a dictionary rather than a string.
Update: Here is my new environment:
MS SQL Server: Microsoft SQL Server 2012 – 11.0.2100.60 (X64)
Feb 10 2012 19:39:15
Copyright (c) Microsoft Corporation
Standard Edition (64-bit) on Windows NT 6.2 (Build 9200: )
Python: 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:43:06) [MSC v.1600 32 bit (Intel)]
Pandas version: ‘0.16.2’
sqlalchemy version: 1.1.3
Jupyter server version : 4.2.3
Now the line
engine = sqlalchemy.create_engine('mssql+pyodbc://localhost/Sandbox?trusted_connection=yes')
generates the following error:
c:python34libsite-packagessqlalchemyconnectorspyodbc.py:82: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
"No driver name specified; "
The likely problem is that you have not specified the driver, so try:
engine = sqlalchemy.create_engine('mssql+pyodbc://localhost/Sandbox?trusted_connection=yes')
This is based on the warning message that you got on the top:
c:python34libsite-packagessqlalchemyconnectorspyodbc.py:82: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
"No driver name specified; "
Note that you can also use pymssql instead of pyodbc, but MS recommends the latter.
EDIT
Here is official documentation on how to connect with/without DSN (data source name):
https://github.com/mkleehammer/pyodbc/blob/master/docs/index.md#connect-to-a-database
You need to specify both that you want to use ODBC and what ODBC driver to use.
engine = sqlalchemy.create_engine('mssql+pyodbc://localhost/Sandbox?driver=SQL+Server+Native+Client+11.0')
Trusted connections are the default, so you don’t need to specify that, although it shouldn’t hurt to do so.
Update:
2022-02-18: The latest ODBC driver for SQL Server seems to be "ODBC Driver 17 for SQL Server". The driver named "SQL Server" is old and should not be used.
@user1718097 gives the useful suggestion of using [x for x in pyodbc.drivers()] to list the installed drivers.
You can also list the installed drivers with the Get-OdbcDriver cmdlet in powershell.
I know the question has been answered for some time now and it’s just a warning, but if you have transferred everything correctly and this error still occurs it’s annoying.
For all those who had to struggle with it like I did, you can also enter the driver directly in the script, Pyodbc.py offers the possibility for this (row 26 – 28):
# for non-DSN connections, this *may* be used to
# hold the desired driver name
pyodbc_driver_name = 'ODBC Driver 17 for SQL Server'
Above information was much useful. Commenting below version of mine as consolidated which can help freshers during search.
#using library pandas and pyodbc – if not available please use pip install commands to install library based on version. Python version used here is 3.7.8
import pandas as pd
from sqlalchemy import create_engine
import pyodbc
#This query will work for sql authentication
def mssql_engine():
engine = create_engine('mssql+pyodbc://type_username:type_password@type_servername_or_localhostname/type_database_name?driver=SQL+Server+Native+Client+11.0')
return engine
#This query will for windows authentication
#Note: Uncomment below code for windows authentication
#def mssql_engine():
#engine = create_engine('mssql+pyodbc://localhostname/db_name?driver=SQL+Server+Native+Client+11.0')
#return engine
query = 'select * from table_name'
#using pandas to read from sql and passing connection string as function
df = pd.read_sql(query, mssql_engine() )
#printing result
print(df)
I ran into a similar problem with SQLModel with an error message like:
SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections return _create_engine(url, **current_kwargs) # type: ignore
Using @cco ‘s response solved the issue:
CONNECTION_URL = f"mssql+pyodbc://{SQL_SERVER_USERNAME}:{SQL_SERVER_PASSWORD}"
f"@{SQL_SERVER_NAME}/{SQL_SERVER_DATABASE}?driver=SQL%20Server"