Sql-server – Connecting to MS SQL Server with Windows Authentication using Python

odbcpyodbcsql serversql-server-2008-r2windows-authentication

How do I connect MS SQL Server using Windows Authentication, with the pyodbc library?

I can connect via MS Access and SQL Server Management Studio, but cannot get a working connection ODBC string for Python.

Here's what I've tried (also without 'Trusted_Connection=yes'):

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='[system_name]',
               database='[databasename]')

pyodbc.connect('Trusted_Connection=yes', uid='me',
               driver='{SQL Server}', server='localhost',
               database='[databasename]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='localhost',
               uid='me', pwd='[windows_pass]', database='[database_name]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='localhost',
               database='[server_name]\\[database_name]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='localhost',
               database='[server_name]\[database_name]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}',
               database='[server_name]\[database_name]')

Best Answer

You can specify the connection string as one long string that uses semi-colons (;) as the argument separator.

Working example:

import pyodbc
cnxn = pyodbc.connect(r'Driver=SQL Server;Server=.\SQLEXPRESS;Database=myDB;Trusted_Connection=yes;')
cursor = cnxn.cursor()
cursor.execute("SELECT LastName FROM myContacts")
while 1:
    row = cursor.fetchone()
    if not row:
        break
    print(row.LastName)
cnxn.close()

For connection strings with lots of parameters, the following will accomplish the same thing but in a somewhat more readable way:

conn_str = (
    r'Driver=SQL Server;'
    r'Server=.\SQLEXPRESS;'
    r'Database=myDB;'
    r'Trusted_Connection=yes;'
    )
cnxn = pyodbc.connect(conn_str)

(Note that there are no commas between the individual string components.)

Syntax:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES

Example:

ALTER TABLE SomeTable
        ADD SomeCol Bit NULL --Or NOT NULL.
 CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated.
    DEFAULT (0)--Optional Default-Constraint.
WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records.

Notes:

Optional Constraint Name:
If you leave out CONSTRAINT D_SomeTable_SomeCol then SQL Server will autogenerate
a Default-Contraint with a funny Name like: DF__SomeTa__SomeC__4FB7FEF6

Optional With-Values Statement:
The WITH VALUES is only needed when your Column is Nullable
and you want the Default Value used for Existing Records.
If your Column is NOT NULL, then it will automatically use the Default Value
for all Existing Records, whether you specify WITH VALUES or not.

How Inserts work with a Default-Constraint:
If you insert a Record into SomeTable and do not Specify SomeCol's value, then it will Default to 0.
If you insert a Record and Specify SomeCol's value as NULL (and your column allows nulls),
then the Default-Constraint will not be used and NULL will be inserted as the Value.

Notes were based on everyone's great feedback below.
Special Thanks to:
@Yatrix, @WalterStabosz, @YahooSerious, and @StackMan for their Comments.

Sql – How to return only the Date from a SQL Server DateTime datatype

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, @your_date))

for example

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, GETDATE()))

gives me

2008-09-22 00:00:00.000

Pros:

No varchar<->datetime conversions required
No need to think about locale

Best Answer

Related Solutions

Sql – Add a column with a default value to an existing table in SQL Server

Syntax:

Example:

Notes:

Sql – How to return only the Date from a SQL Server DateTime datatype

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