How do I access the query that feeds the grid?

I have one table. I want to add something like:

WHERE USER_ID = CURRENT_USER_ID

So that each user can only see their own records on the front end.

Where do I put this in a fork ?
What do I use for CURRENT_USER_ID?

or username if that is easier?

I guess you have seen my previous post answering for your publish problem.

The query construction is in only ONE place for each model. -> prepareQuery()

Yes,
it is working now by using un-publish.

That will work for now.

Thank you.