PHP: Query Result Loops

Pro Tip: when you loop through the results of a query like this:

while ( $theDatabase->getNextRow() ) {
    //... do a ton of stuff ...

I would like to point out that it will fail eventually. Why? Oh there’s nothing wrong with it, per se…

But if somewhere in all of that ton of stuff inside the while loop you ask the database for something else (like a small list of items for a drop down control), then when you get back to the “while” line, it will now either return the wrong data row or most likely just end prematurely — because of lazy coding!

All that is needed to avoid this hard to detect bug, is to save off the query result given in the first line and use it in the “while” line. No question now which row will be returned and everything will be correct no matter how many nested database calls you put inside the while loop.

$theQueryResult = $theDatabase->getSqlData($theSQLtext);
while ( $theDatabase->getNextRow($theQueryResult) ) {
    //... do a ton of stuff...

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