How to Reset the Array Pointer in PDO Results After `fetchAll()`?

PDO Results Array Pointer Reset – A Detailed Solution

Introduction

Migrating from MySQL SELECT methods to PDO methods can introduce challenges. Resetting the array pointer, which allows iterating through a fetched array multiple times, is one such challenge.

The Problem

In MySQL, the mysql_data_seek() function achieves this pointer reset. However, in PDO, this function is not available. As exemplified in the provided code, subsequent loops starting from row zero return no results.

The Solution

To overcome this issue, store the fetched results in an array and iterate over that array multiple times. This modified code demonstrates the solution:

$pdo = new PDO('mysql:host=' . $host . ';dbname='.$database, $username, $password);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$stmt = $pdo->prepare('SELECT * FROM mytable WHERE active = 1 ORDER BY name ASC');
$stmt->setFetchMode(PDO::FETCH_ASSOC);
$stmt->execute();

$rows = $stmt->fetchAll();

foreach ($rows as $r) {
    // first run
}

foreach ($rows as $r) {
    // seconds run
}

Additional Context

• The fetchAll() method collects all results into an array.
• Iterating over the $rows array ensures that the pointer always starts at the first row in each loop.

By implementing this solution, you can effectively reset the array pointer in PDO results, allowing you to iterate through the fetched array multiple times starting from row zero.

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