// Update a single field of the user and verify that the changed address is not stored.
	newAge := uint(100)
	user.Account.Number = "new_account_number"
	db := DB.Model(&user).UpdateColumns(User{Age: newAge})

	if db.RowsAffected != 1 {
		t.Errorf("Expected RowsAffected=1 but instead RowsAffected=%v", db.RowsAffected)
	}

	// Verify that Age now=`newAge`.
	result := &User{}
	result.ID = user.ID
	DB.Preload("Account").First(result)