Failed to update data model parameters - using new October update way to change connection string

[Martin51]

Hello,

I am trying to change the connection string using parameters, as described on this page: Change data source connection strings with PowerShell - Power BI | Microsoft Docs.

When I create a new Power BI report, everything works fine and I am able to modify the parameter (and thus the connection string).

But when adding a parameter to an existing Power BI report, I am not able to modify the value and get the following error message: 

Failed to update data model parameters for [report path] The remote server returned an error: (500) Internal Server Error.

As described on the page, I first get the parameters with the Get-RsRestItemDataModelParameters function, then I modify the value and I use Set-RsRestItemDataModelParameters to apply to the report server.

Report server version: 9.7627.11028 (October 2020)

ReportingServicesTools PowerShell module : 0.0.5.9

Your help is very much appreciated,

Best regards,

Martin B.

[Martin51]

Hello,

I am not using a list of values but just a default value. This parameter is used as connection string in the data source settings. I would like to programatically change the value via PowerShell , in order to modify the connection string during deployment to another environment. I have now more information about the error, this is what the report server logs shows: An item with the same key has already been added.

2021-01-07 16:17:57.8626|INFO|572|Received request POST /api/v2.0/PowerBIReports(Path='/TestReport')/DataModelParameters| RequestID = s_adfa12bb-a254-4bac-bdc9-41dd77cb36d7
2021-01-07 16:17:58.7062|ERROR|515|OData exception occurred: System.ArgumentException: An item with the same key has already been added.
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at Microsoft.ReportingServices.Portal.Repositories.CatalogItemRepository.SetDataModelDataSourcesTrusted(IPrincipal userPrincipal, Guid itemId, IEnumerable`1 dataSources, Boolean isOverwrite)
at Microsoft.ReportingServices.Portal.ODataWebApi.V2.Controllers.PowerBIReportsController.<PostDataModelParameters>d__33.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Threading.Tasks.TaskHelpersExtensions.<CastToObject>d__1`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__6.MoveNext().| RequestID = s_adfa12bb-a254-4bac-bdc9-41dd77cb36d7

[V-pazhen-msft]

@Martin51 

How did you set up your parameter, you should have a list of names under Server Name and Database Name (the doc didn't mention), so you can edit parameter to switch between servers and databases. You can took a look at the desktop parameter that is same as Desktop for Report Server, this blog explains parameter in detail: Using Parameters in Power BI (mssqltips.com).

Paul Zheng _ Community Support Team
If this post helps, please Accept it as the solution to help the other members find it more quickly.

[Martin51]

I am working with the on-premises Power BI report server. I am now using the Invoke-RestMethod. I get an error but without any message: 

Invoke-RestMethod : {"error":{"code":"0","message":""}}.

[lbendlin]

Please confirm if you are working with Power BI Report Server or with the regular Power BI Service.

For Service: Try doing the same call in the Power BI API sandbox.  If that works, use the basic 

Invoke-RestMethod (Microsoft.PowerShell.Utility) - PowerShell | Microsoft Docs

 or  the slightly more luxurious

Invoke-PowerBIRestMethod (MicrosoftPowerBIMgmt.Profile) | Microsoft Docs

instead of your cmdlets.