DataFlow is not replacing table in Fabric OneLake

[jaryszek]

Hi Guys,

I have a table like this:

and this is coming from this query in dataflow:

what i have done , i added the new step to add new test column into this and run "Save & Run":

But new column eventhough the Update method is replaced...didnt work! Why? 

new column is not appearing in OneLake environment...

Best,
Jacek

[rohit1991 · Accepted solution]

Hi @jaryszek 

When you add a new column in a Dataflow and run Save & Run, the change is applied inside the dataflow but it doesn’t always show up in OneLake unless the output settings are refreshed. The “Update method = Replace” only overwrites the table structure that was already mapped, but if the schema in OneLake isn’t refreshed, the new column won’t appear.

Here are a few things to check:

1. Confirm the destination mapping : In the Dataflow output settings, go to Column mapping and make sure the new column is mapped to the OneLake table. If it’s not mapped, OneLake won’t include it.

2. Run a full refresh : Sometimes incremental or cached runs don’t push schema changes. Try running a full refresh of the dataflow.

3. Verify OneLake table schema : Open the table in OneLake Explorer or SQL Endpoint and check if the column exists at the schema level. If it doesn’t, the mapping didn’t apply.

4. Consider schema drift settings : If your workspace has schema enforcement on, new columns may be blocked until you explicitly allow schema drift or remap the output.

[v-aatheeque]

Hi @jaryszek 

We haven’t heard back from you on the response provided by @rohit1991  and just wanted to check if your query has been resolved. If not, please share more details so we can assist you further.

[v-aatheeque]

Hi @jaryszek 

Just checking in to see if you had a chance to review the previous response. If you still need assistance, please let us know and we’ll be glad to help.