Add external data to Azure sql table - add or replace the original data?

Question

Hi team,
I will load external data into an existing Azure sql data table via ADF (copy data). My question is: the new dataset loaded will replace the old dataset or the new dataset will be appended to previous dataset?
If new dataset were appended to old dataset, how about the duplicated rows between new and old dataset? keep duplicates or drop duplicates? Thanks
Best,
GZ

Answer 1

By default it will append to the existing data unless you also include a task to delete all the records or truncate the table.

You will need to manage the handling of updated rows separately - I would suggest that you load into a temporary table and then use the T-SQL
MERGE
command to move and update the rows into the final table.