topic Re: Publishing a User Data Function is giving error in Data Engineering

Publishing a User Data Function is giving error

VivekGoli1203 — Fri, 27 Jun 2025 06:29:51 GMT

I have created a Fabric SQL Database. Created a User Data Function and added the connection to SQL Database in Manage Connections section of the UDF. Then I have pasted the sample code that Microsoft Tutorial has given. Publishing the UDF is giving the below error.

Unexpected token '<', "<!--# QVsM"... is not valid JSON

Link to tutorial : https://learn.microsoft.com/en-us/power-bi/create-reports/translytical-task-flow-tutorial

Re: Publishing a User Data Function is giving error

v-prasare — Sat, 28 Jun 2025 05:34:09 GMT

Hi @VivekGoli1203,

we are looking to your scenario and will post answer once were tried reproducing it.

Thanks,

Prashanth Are

MS Fabric community support

Re: Publishing a User Data Function is giving error

VivekGoli1203 — Mon, 30 Jun 2025 05:26:14 GMT

Hello Prashanth, Please respond if you find any solution

Re: Publishing a User Data Function is giving error

v-prasare — Mon, 30 Jun 2025 09:33:21 GMT

Hi @VivekGoli1203,

As i have tried and implimeted below mentioned: Create a translytical task flow (https://learn.microsoft.com/en-us/power-bi/create-reports/translytical-task-flow-tutorial#test-the-sample-code)

when i run the UDF mentioned in the docs, it gives me success message without any errors. Can you try again once replacing the default code with the code given in the documentation. there might have been extra typos mistakes have added while copying code that might result in error.

Thanks,

Prashanth Are

MS Fabric community support

If my answer helps please accept as solution, by doing this users with similar issues find answers easily.

Re: Publishing a User Data Function is giving error

VivekGoli1203 — Fri, 04 Jul 2025 05:07:23 GMT

I have used the correst code from the turorial, with correct data connection to Fabric SQL Database.

But it has given error in my tenant. But in other tenant of our organisation it worked fine.

Re: Publishing a User Data Function is giving error

v-prasare — Mon, 07 Jul 2025 15:27:04 GMT

In this scenario i suggest you to raise a support ticket here. so, that they can assit you in addressing the issue you are facing. please follow below link on how to raise a support ticket:

How to create a Fabric and Power BI Support ticket - Power BI | Microsoft Learn

Thanks,

Prashanth Are

MS Fabric community support

Re: Publishing a User Data Function is giving error

VivekGoli1203 — Tue, 08 Jul 2025 05:52:15 GMT

Okay Prashanth thank you

Re: Publishing a User Data Function is giving error

BhaveshPatel — Tue, 08 Jul 2025 09:06:19 GMT

Just curious that why do we need User Data Function in Fabric SQL Database?? Use Kimball methodology/ Dimensional Modelling wherever we can. ( DimTable <--> Fact Table )

Re: Publishing a User Data Function is giving error

VivekGoli1203 — Tue, 08 Jul 2025 09:08:06 GMT

I am trying to implement write back in a Power Bi report, so as per the newly introduced translytical workflows tutorial it asked to create a UDF that takes values from report as parameters and updates them in the Fabric SQL Database.

Re: Publishing a User Data Function is giving error

BhaveshPatel — Wed, 09 Jul 2025 05:43:51 GMT

This write back functionlity in Power BI is not available in User Defined Functions. You should do (write back functionilty) this in DWH aka Data Lakehouse. ( in Apache Spark with Python and INSERT ) . I will give you an example:

Writing data back to Azure SQL Database

# Create DataFrame to insert into the Azure SQL table ( Writing Data to Azure SQL Table )

df1 = spark.createDataFrame([('WL2456', 'Luke1293', 'Skywalker','Null','Null',-3,'Unknown','Unknown','Null')], ['DeviceID', 'DeviceName', 'DeviceDesc','OperatorName','OperatorDesc','FacilityID','FacilityName','FacilityDesc','DeviceSerialNo'])

# Insert the rows into the Azure SQL table

df1.write \

.option('user', user) \

.option('password', pswd) \

.jdbc('jdbc:sqlserver://' + sqlserver + ':' + port + ';database=' + database, 'dbo.Devices', mode = 'append' )

df1.show()