Working with databases in PHP
Your code looks like its good quality code. And yes, you’re right to be concerned. Most likely, after you’re gone, somebody else will (eventually) maintain, or change the code that you’ve written to date. I suggest that you comment and write the code so that a maintainer understands its purpose at first read.

For example ...

/*
 * Look quickly over the database to make sure nothing else is signed that ought to be unsigned.
 * TODO: Explain why unsigned is better than signed…
 */

$db = Database::instance();
$all_tables = array();
$result = $db-&gt;query('SHOW TABLES');
foreach($result as $unique_table)
{
   $show_created_table = $db-&gt;query("SHOW CREATE TABLE `".current($unique_table)."`");
   $all_tables[current($show_created_table-&gt;current())] = end($show_created_table-&gt;current());
}
echo var_dump($all_tables);


It's worth doing for yourself, for memory sake, if you haven't touched the code for a longtime.
It will also help the maintainer understand the intented purpose of the function. Now, if your project is large and complex, I'd recommend that you use phpdoc -- it's a good standard.