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Hoping's avatar
Hoping
Icon for Helper III rankHelper III
2 years ago
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New columns to table added at source

Is it a recent change to Power BI service that new columns added to the table / view in the source database or warehouse will not flow through to the semantic model ?   As a concequence we have to up...
  • Martin_D's avatar
    2 years ago

    Hi Hoping ,

    I'd be surprised if columns were added automatically upon refresh. In the tabular model there is a static binding between semantic model columns and source columns. The columns you see is a static definition as part of the model, not coming dynamically from the source.

    The reason is that data refreshes are technically partition refreshes, even if Power BI tables have only one partition except for incremental refresh tables. Since different partitions of the same table cannot have diffrent schemas, schema won't update upon refresh. There is no refresh type that includes a schema update. https://learn.microsoft.com/en-us/rest/api/power-bi/datasets/refresh-dataset#datasetrefreshtype

    If you refresh data in Power BI Desktop this includes a schema update and an update of all partitions (including a full table, all partitions update of tables for which incremental refresh is configured). With Premium workspaces you could implement this yourself, writing a script that first does the schema update through XMLA and then triggers the data refresh. Adding a new column is always an explicit schema update of the tabular model. Update Tabular Model when the underlying Relational Database schema changes | Microsoft Learn

    Kind regrds,

    Martin