As Mark pointed out, pipelining is generally used for a series of transformations. Your code performs a series of actions. I recommend writing it like this:
// find file for deletion
let findFileToDelete id =
let row =
query {
for row in db.Uploads do
where (row.Id = id)
exactlyOneOrDefault
}
File.Delete row.FilePath
deleteRowFrom db.Uploads row
// update the database
saveToDb()