Update schema of large semantic models

Hi julsr ,

Thank you for reaching out to the Microsoft Community Forum.

By using SSMS + TMSL you can update a Power BI semantic model without opening Power BI Desktop. It works ONLY if your workspace is on a Premium / Fabric F/SK capacity because it requires XMLA read/write.

Please try below steps.

1. In Power BI Service, Open your workspace --> Go to Settings --> Premium / Fabric capacity. Copy the XMLA endpoint URL:

powerbi://api.powerbi.com/v1.0/myorg/SalesWorkspace

2. In SSMS, Open SQL Server Management Studio --> Click Connect --> Analysis Services. Enter the XMLA endpoint URL.

3. Authentication, Azure Active Directory - Universal (with MFA). Sign in with your Power BI account. After connecting, you will see all datasets as “databases”.

4. Right-click the Dataset --> New Query --> XMLA. This opens a query window where you can run TMSL(Tabular Model Scripting Language) scripts. Execute through an XMLA connection.

To Rename a Column refer below JSON code.

{
"alter": {
"object": {
"database": "ModelName",
"table": "FactSales",
"column": "OldColumnName"
},
"renameTo": "NewColumnName"
}
}

To Add a New Column refer below JSON code.

{
"alter": {
"object": { "database": "ModelName" },
"script": "{
\"tables\": [{
\"name\": \"FactSales\",
\"columns\": [{
\"name\": \"NewCol\",
\"dataType\": \"string\"
}]
}]
}"
}
}

Please refer below link.

Tabular Model Scripting Language (TMSL) Reference | Microsoft Learn

I hope this information helps. Please do let us know if you have any further queries.

Regards,

Dinesh