PDO fetchAll: Efficiently Group Key-Value Pairs in an Associative Array
When handling database queries that retrieve key-value pairs, extracting these values into an associative array can be a common requirement. However, the standard approach involving PDO::FETCH_ASSOC followed by manual array manipulation can be tedious and inefficient. This article explores an alternative solution that leverages the lesser-known PDO::FETCH_KEY_PAIR parameter to simplify this process.
Problem: Given a query like SELECT 'key', 'value' FROM 'settings', the goal is to obtain an associative array with key-value pairs extracted efficiently.
Solution: To avoid the need for manual data manipulation, PDO offers the PDO::FETCH_KEY_PAIR option in its fetchAll method. This parameter instructs PDO to automatically assemble key-value pairs into an associative array, saving significant time and effort.
To illustrate this solution:
$q = $db->query("SELECT `name`, `value` FROM `settings`;"); $r = $q->fetchAll(PDO::FETCH_KEY_PAIR);
In this example, $db represents the PDO connection object. The fetchAll method retrieves all rows from the query result, and PDO::FETCH_KEY_PAIR specifies that the keys and values should be paired into an associative array. The resulting $r variable is an associative array with name as keys and value as corresponding values.
This optimized approach eliminates the need for additional array manipulation, making it a more efficient and concise solution for grouping key-value pairs from database queries.
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