使用 Python 连接到 Microsoft SQL 服务器

Question

I am trying to connect to SQL through python to run some queries on some SQL databases on Microsoft SQL server. From my research online and on this forum the most promising library seems to be pyodbc. So I have made the following code

import pyodbc
conn = pyodbc.connect(init_string="driver={SQLOLEDB}; server=+ServerName+; 
database=+MSQLDatabase+; trusted_connection=true")
cursor = conn.cursor()

and get the following error

Traceback (most recent call last):
  File "C:\Users...\scrap.py", line 3, in <module>
    conn = pyodbc.connect(init_string="driver={SQLOLEDB}; server=+ServerName+; database=+MSQLDatabase+; trusted_connection=true")
pyodbc.Error: ('IM002', '[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)')

I have looked at the folowing posts and tried changing my driver to {sql server} and have connected using ODBC links before in SAS, which is partially what my above code is based on, so don't think I need to install anything else.

pyodbc.Error: ('IM002', '[IM002] [unixODBC][Driver Manager]Data source name not found, and no default driver specified (0) (SQLDriverConnect)')

Pyodbc - "Data source name not found, and no default driver specified"

Thanks

Answer 1

This is how I do it...

import pyodbc 
cnxn = pyodbc.connect("Driver={SQL Server Native Client 11.0};"
                      "Server=server_name;"
                      "Database=db_name;"
                      "Trusted_Connection=yes;")


cursor = cnxn.cursor()
cursor.execute('SELECT * FROM Table')

for row in cursor:
    print('row = %r' % (row,))

Relevant resources:

• https://github.com/mkleehammer/pyodbc/wiki/Connecting-to-SQL-Server-from-Windows

• http://blogs.msdn.com/b/cdndevs/archive/2015/03/11/python-and-data-sql-server-as-a-data-source-for-python-applications.aspx

Answer 2

Minor addition to what has been said before. You likely want to return a dataframe. This would be done as

import pypyodbc 
import pandas as pd

cnxn = pypyodbc.connect("Driver={SQL Server Native Client 11.0};"
                        "Server=server_name;"
                        "Database=db_name;"
                        "uid=User;pwd=password")
df = pd.read_sql_query('select * from table', cnxn)

Answer 3

In data source connections between a client and server there are two general types: ODBC which uses a DRIVER and OLEDB which uses a PROVIDER. And in the programming world, it is a regular debate as to which route to go in connecting to data sources.

You are using a provider, SQLOLEDB , but specifying it as a driver. As far as I know, neither the pyodbc nor pypyodbc modules support Window OLEDB connections. However, the adodbapi does which uses the Microsoft ADO as an underlying component.

Below are both approaches for your connection parameters. Also, I string format your variables as your concatenation did not properly break quotes within string. You'll notice I double the curly braces since it is needed in connection string and string.format() also uses it.

# PROVIDER
import adodbapi
conn = adodbapi.connect("PROVIDER=SQLOLEDB;Data Source={0};Database={1}; \
       trusted_connection=yes;UID={2};PWD={3};".format(ServerName,MSQLDatabase,username,password))
cursor = conn.cursor()

# DRIVER
import pyodbc
conn = pyodbc.connect("DRIVER={{SQL Server}};SERVER={0}; database={1}; \
       trusted_connection=yes;UID={2};PWD={3}".format(ServerName,MSQLDatabase,username,password))
cursor = conn.cursor()

Answer 4

I Prefer this way ... it was much easier

http://www.pymssql.org/en/stable/pymssql_examples.html

conn = pymssql.connect("192.168.10.198", "odoo", "secret", "EFACTURA")
cursor = conn.cursor()
cursor.execute('SELECT * FROM usuario')

Answer 5

Following Python code worked for me. To check the ODBC connection, I first created a 4 line C# console application as listed below.

Python Code

import pandas as pd
import pyodbc 
cnxn = pyodbc.connect("Driver={SQL Server};Server=serverName;UID=UserName;PWD=Password;Database=My_DW;")
df = pd.read_sql_query('select TOP 10 * from dbo.Table WHERE Patient_Key > 1000', cnxn)
df.head()

Calling a Stored Procedure

 dfProcResult = pd.read_sql_query('exec dbo.usp_GetPatientProfile ?', cnxn, params=['MyParam'] )

C# Program to Check ODBC Connection

    static void Main(string[] args)
    {
        string connectionString = "Driver={SQL Server};Server=serverName;UID=UserName;PWD=Password;Database=My_DW;";
        OdbcConnection cn = new OdbcConnection(connectionString);
        cn.Open();
        cn.Close();
    }

Answer 6

Try using pytds, it works throughout more complexity environment than pyodbc and more easier to setup.

I made it work on Ubuntu 18.04

Ref: https://github.com/denisenkom/pytds

Example code in documentation:

import pytds
with pytds.connect('server', 'database', 'user', 'password') as conn:
    with conn.cursor() as cur:
        cur.execute("select 1")
        cur.fetchall()

Answer 7

Here are some pics for newbies.

Answer 8

Try with pymssql : pip install pymssql

import pymssql

try:
    conn = pymssql.connect(server="host_or_ip", user="your_username", password="your_password", database="your_db")
    cursor = conn.cursor()
    cursor.execute ("SELECT @@VERSION")
    row = cursor.fetchone()
    print(f"\n\nSERVER VERSION:\n\n{row[0]}")
    cursor.close()
    conn.close()
except Exception:
    print("\nERROR: Unable to connect to the server.")
    exit(-1)

Output:

SERVER VERSION:

Microsoft SQL Server 2016 (SP2-CU14) (KB4564903) - 13.0.5830.85 (X64)
        Jul 31 2020 18:47:07
        Copyright (c) Microsoft Corporation
        Standard Edition (64-bit) on Windows Server 2012 R2 Standard 6.3 <X64> (Build 9600: ) (Hypervisor)

The connection can also be checked from the terminal, with a single line of code with sqlcmd . See syntax .

╔═════════╦═════════════════════════════════════════╗
║ Command ║               Description               ║
╠═════════╬═════════════════════════════════════════╣
║   -S    ║ [protocol:]server[instance_name][,port] ║
║   -U    ║ login_id                                ║
║   -p    ║ password                                ║
║   -Q    ║ "cmdline query" (and exit)              ║
╚═════════╩═════════════════════════════════════════╝

sqlcmd -S "host_or_ip"  -U "your_username" -p -Q "SELECT @@VERSION"

output:

Password:    your_password



--------------------------------------------------------------------------------------------------------------------------------------------------------
Microsoft SQL Server 2016 (SP2-CU14) (KB4564903) - 13.0.5830.85 (X64) 
        Jul 31 2020 18:47:07 
        Copyright (c) Microsoft Corporation
        Standard Edition (64-bit) on Windows Server 2012 R2 Standard 6.3 <X64> (Build 9600: ) (Hypervisor)


(1 rows affected)

Network packet size (bytes): 4096
1 xact[s]:
Clock Time (ms.): total         1  avg   1.00 (1000.00 xacts per sec.)

Answer 9

here's the one that works for me:

from sqlalchemy import create_engine
import urllib
import pandas

conn_str = (
r'Driver=ODBC Driver 13 for SQL Server;'
r'Server=DefinitelyNotProd;'
r'Database=PlayPen;'
r'Trusted_Connection=Yes;')

quoted_conn_str = urllib.parse.quote_plus(conn_str)
engine = create_engine('mssql+pyodbc:///?odbc_connect={}'.format(quoted_conn_str))
sqlcmd = """select * from information_schema.tables"""
df = pd.read_sql(sqlcmd, engine)

Answer 10

I tried to connect sql server in following ways and those worked for me.

To connect using windows authentication

import pyodbc

conn = pyodbc.connect('Driver={SQL Server};Server='+servername+';Trusted_Connection=yes;Database='+databasename+';')
cursor = conn.cursor()
cursor.execute("Select 1 as Data")

To use sql server authentication I used following code.

import pyodbc

conn = pyodbc.connect('Driver={SQL Server};Server='+servername+  ';UID='+userid+';PWD='+password+';Database='+databasename) 
cursor1 = conn.cursor()
cursor1.execute("SELECT 1 AS DATA")

Answer 11

An alternative approach would be installing Microsoft ODBC Driver 13, then replace SQLOLEDB with ODBC Driver 13 for SQL Server

Regards.

Answer 12

I found up-to-date resources here: Microsoft | SQL Docs | Python SQL Driver

There are these two options explained including all the prerequisites needed and code examples: Python SQL driver - pyodbc (tested & working) Python SQL driver - pymssql

Answer 13

My version. Hope it helps.

import pandas.io.sql
import pyodbc
import sys

server = 'example'
db = 'NORTHWND'
db2 = 'example'

#Crear la conexión
conn = pyodbc.connect('DRIVER={SQL Server};SERVER=' + server +
                      ';DATABASE=' + db +
                      ';DATABASE=' + db2 +
                      ';Trusted_Connection=yes')
#Query db
sql = """SELECT [EmployeeID]
      ,[LastName]
      ,[FirstName]
      ,[Title]
      ,[TitleOfCourtesy]
      ,[BirthDate]
      ,[HireDate]
      ,[Address]
      ,[City]
      ,[Region]
      ,[PostalCode]
      ,[Country]
      ,[HomePhone]
      ,[Extension]
      ,[Photo]
      ,[Notes]
      ,[ReportsTo]
      ,[PhotoPath]
  FROM [NORTHWND].[dbo].[Employees] """
data_frame = pd.read_sql(sql, conn)
data_frame

Answer 14

This is how I had done it.

import pyodbc



connection = pyodbc.connect("DRIVER={SQL Server Native Client 10.0};"
                            
                            "SERVER=server_name;"
                            
                            "DATABASE=database_name;"
                            
                            "UID=user_id_of_database;"
                            
                            "PWD=password_of_database;")


cursor = connection.cursor()

cursor.execute('SELECT * FROM Table')


Always make sure you had specified the correct Driver. You can check your Driver by following the steps given below.

1. Open the Windows Control Panel.
2. Open the Administrative Tools folder.
3. Double-click Data Sources (ODBC) to open the ODBC Data Source Administrator window.
4. Click the Drivers tab