Achieving Efficient Key-Value Array Conversion from Database Queries Using PDO

In database manipulation scenarios, extracting data from a table into an associative array often arises. For queries featuring a key-value structure, the traditional approach involves two steps: fetching the results into a flat array and subsequently iterating through it to construct the desired associative array.

Nevertheless, an alternative solution exists that directly returns the associative array from the database query. Using the PDO fetchAll method with the PDO::FETCH_KEY_PAIR constant, one can achieve this efficiently:

$q = $db->query("SELECT `name`, `value` FROM `settings`;");
$r = $q->fetchAll(PDO::FETCH_KEY_PAIR);

This solution eliminates the need for additional processing and significantly simplifies the code. Notably, its compatibility with PostgreSQL 9.1 and PHP 5.3.8 makes it a viable option for a wide range of applications.