Hello Sharon,
The FD_ column is not documented yet because internal to our integration process when deleting a parent record (FD standing for Foreign Delete). It should not be filled when integrating data.
That being said, we understand that as it is present in the tables of the data location, developers would like to better understand its usage, hence why we have created an internal request to that purpose: DOC-562.
I hope this helps.
Have a good day.
Alexia
Sharon GEORGE
What is the definition of the FD_ column in SD tables? I tried searching xDM documentation but could not find the answer.