Write dataframe support #695

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1. github-actions commented on Jul 31, 2026

   

   github-actionsBot

   on Jul 31, 2026 – with GitHub Actions

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   Hi ak (@akommera), thank you for opening this issue!

   Our team will review it shortly. We aim to triage all new issues within 24-48 hours and get back to you.

   If you have additional information to share, please feel free to update the issue.

   Thank you for your patience!
2. github-actions

   added

   triage neededFor new issues, not triaged yet.For new issues, not triaged yet.

   on Jul 31, 2026
3. gordthompson commented on Aug 2, 2026

   

   Gord Thompson (gordthompson)

   on Aug 2, 2026

   Last edited by gordthompson

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   If you are working from the polars documentation here

   https://docs.pola.rs/user-guide/io/database/#sqlalchemy

   be aware that support for mssql-python is included in SQLAlchemy 2.1, which is currently in beta. So, your command to install the additional dependencies should be

   $ pip install SQLAlchemy==2.1.0b3 mssql-python pandas pyarrow
   

   and your example code should look like this

   uri = "mssql+mssqlpython://username:password@server:port/database"
   df = pl.DataFrame({"foo": [1, 2, 3]})
   
   df.write_database(table_name="records",  connection=uri)

   👍React with 👍1Reacted by ak
4. arkdvd commented on Aug 3, 2026

   

   arkdvd

   on Aug 3, 2026

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   What should be connection string for win auth?
5. gordthompson commented on Aug 3, 2026

   

   Gord Thompson (gordthompson)

   on Aug 3, 2026

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   According to

   https://docs.sqlalchemy.org/en/21/dialects/mssql.html#connection-strings

   that would be

   uri = "mssql+mssqlpython://hostname/database?authentication=ActiveDirectoryIntegrated"
6. arkdvd commented on Aug 3, 2026

   

   arkdvd

   on Aug 3, 2026

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   Error:
   ConnectionStringParseError: Connection string parsing failed:
   Incomplete specification: keyword '{' has no value (missing '=')
   Unknown keyword 'authentication}' is not recognized

   uri = "mssql+mssqlpython://hostname\Instancename:portnum/database?authentication=ActiveDirectoryIntegrated"
   uri = "mssql+mssqlpython://hostname\Instancename/database?authentication=ActiveDirectoryIntegrated"

   Ran with all these libs :
   Name: SQLAlchemy
   Version: 2.1.0b3

   Name: pandas
   Version: 3.0.1

   Name: pyarrow
   Version: 25.0.0

   Name: mssql-python
   Version: 1.12.0
7. Subrata (subrata-ms)

   self-assigned this

   on Aug 4, 2026
8. subrata-ms commented on Aug 5, 2026

   

   Subrata (subrata-ms)

   on Aug 5, 2026

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   Hi ak (@akommera), arkdvd , I was unable to reproduce the issue on my end. The two connection strings shared earlier are being parsed correctly when using SQLAlchemy 2.1.0b3 together with the mssql-python driver, and I do not observe any parsing-related problems.
   The specific two-line error message you're seeing is typically generated only when the connection string that ultimately reaches mssql_python.connect() contains an unbalanced {...} segment that spans across a ; delimiter and closes immediately before a = pair. For example:
   Server=host\Inst;{ ;authentication}=ActiveDirectoryIntegrated;Database=db
   ^ ^
   stray '{' closing '}' ends up on the 'authentication' side
   The parser processes the connection string by splitting it into tokens separated by ;. In the example above, it encounters:

   1. { alone → "Incomplete specification: keyword '{' has no value (missing '=')"
   2. authentication}=... → key parsed as literal authentication} → "Unknown keyword 'authentication}' is not recognized"

   Next Steps
   My current hypothesis is that the parsing error is not being caused by the URI itself. Instead, it appears that something in the environment may be modifying the connection string and injecting additional braces around a key=value segment before it reaches the driver.
   Could you please run the following script in the environment where the issue occurs and share the output from the print() statement?

   Script:
   import sqlalchemy as sa

   uri = r"mssql+mssqlpython://hostname\Instancename:portnum/database?authentication=ActiveDirectoryIntegrated"

   url = sa.engine.make_url(uri)
   engine = sa.create_engine(uri)
   print(engine.dialect.create_connect_args(url))

   For a correctly parsed connection string, we would expect output similar to:
   (('Server=hostname\Instancename,1433;Database=database;Authentication=ActiveDirectoryIntegrated',), {})

   This output will help us determine whether the connection string is being altered before it reaches the mssql-python driver and narrow down the source of the issue.
9. Subrata (subrata-ms)

   added

   questionFurther information is requestedFurther information is requested

   triage doneIssues that are triaged by dev team and are in investigation.Issues that are triaged by dev team and are in investigation.

   discussion

   and removed

   triage neededFor new issues, not triaged yet.For new issues, not triaged yet.

   on Aug 6, 2026
10. gordthompson commented on Aug 6, 2026

    

    Gord Thompson (gordthompson)

    on Aug 6, 2026

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    FWIW, I prefer to use URL.create() wherever possible. It avoids string parsing, handles "funny" characters in attributes (e.g., passwords), etc..

    import polars as pl
    import sqlalchemy as sa
    
    engine = sa.create_engine(
        sa.engine.URL.create(
            drivername="mssql+mssqlpython",
            username="scott",
            password="tiger^5HHH",
            host=r"192.168.0.182\SQLEXPRESS01",
            database="test",
            query={"TrustServerCertificate": "yes"},
        )
    )
    
    df = pl.DataFrame({"foo": [1, 2, 3]})
    
    df.write_database(table_name="records", connection=engine)
11. subrata-ms commented on Aug 12, 2026

    

    Subrata (subrata-ms)

    on Aug 12, 2026

    Contributor

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    Hi ak (@akommera) , arkdvd
    I’m closing this bug for now as we need some additional information to continue the investigation. Please feel free to reopen the bug once the requested data is available, and we’ll be happy to resume the analysis.

    Thanks
    Subrata
12. Subrata (subrata-ms)

    closed this as completedon Aug 12, 2026
13. arkdvd commented on Aug 12, 2026

    

    arkdvd

    on Aug 12, 2026

    Last edited by arkdvd

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    This is what I see from parsing:

    (('Server=HOSTNAME;Database=INSTANCENAME:PORTNUM/DATABASE;Authentication=ActiveDirectoryIntegrated',), {})

    And still doesnt work, error message:
    (mssql_python.exceptions.OperationalError) Driver Error: Client unable to establish connection; DDBC Error: [Microsoft]Named Pipes Provider: Could not open a connection to SQL Server [2].
    (Background on this error at: https://sqlalche.me/e/21/e3q8)