The error message "Expression.Error: The key didn't match any rows in the table" suggests that Power BI is unable to find the specified key or row in the Oracle database table. This might occur if the data structure has changed or if there are issues with the key values being used in your query.
Steps to Resolve the Error:
Check the Key Column:
Verify that the key column you are using in your query exists in the Oracle table and that it contains valid data.
Ensure there are no changes to the data types or column names in the Oracle database that might have caused this mismatch.
Review Query Dependencies:
If your Power BI query depends on other queries or tables, ensure those are functioning correctly and returning the expected data.
Refresh the Connection:
Sometimes, a simple refresh of the data connection can resolve mismatches. In Power BI Desktop, try refreshing the dataset to see if the error persists.
Check for Data Transformation Issues:
If your query includes transformations (like filters, joins, or custom columns), review these steps to ensure they are correctly applied to the current data structure.
Edit the Query:
Go to the Power Query Editor and manually inspect the steps applied to the data. This can help you identify where the key mismatch is happening.
You can also remove or adjust problematic steps that reference keys or rows that no longer exist in the data.
Review Oracle Table Permissions:
Ensure that the Oracle database user account used in the Power BI connection has sufficient permissions to access the table and its rows.
Error Handling:
Implement error handling or checks in your Power BI query to manage missing or mismatched keys, using functions like Table.SelectRows or try...otherwise expressions to avoid the error.
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