Fetch string to pass through writeTemporary() in DatabaseOracle.php

Pulled some code from insertOneRow() to fix the update() function
and prevent the error warnings in bugzilla 64970 from showing up.
Note that since insertOneRow() and update() contains a lot of
duplicate code, they may be candidates for merging, but that is
outside the scope of this request.

Bug: 64970
Change-Id: I9ff9077d68e77f05f878fc541f87e0a5ce86ecc2
Merge "Fetch string to pass through writeTemporary() in DatabaseOracle.php"