Optimizing Multiple Row Insertion in PHP PDO MySQL

When faced with the need to insert multiple rows into a MySQL database using PHP's PDO, there are two primary approaches to consider. Let's explore these options and determine the best practice for performance and security.

Approach 1: Individual Row Insertion

This approach involves preparing a statement for each row to be inserted:

$rows = [(1,2,3), (4,5,6), (7,8,9) ... ];

$sql = "insert into `table_name` (col1, col2, col3) values (?,?,?)";

$stmt = $db->prepare($sql);

foreach($rows as $row) {
  $stmt->execute($row);
}

While this method is straightforward, it requires multiple prepare and execute operations. This can impact performance, especially for large datasets.

Approach 2: Batched Row Insertion

This approach leverages the underlying MySQL batching mechanism:

$rows = [(1,2,3), (4,5,6), (7,8,9) ... ];

$sql = "insert into `table_name` (col1, col2, col3) values ";

$paramArray = array();

$sqlArray = array();

foreach($rows as $row) {
    $sqlArray[] = '(' . implode(',', array_fill(0, count($row), '?')) . ')';

    foreach($row as $element) {
        $paramArray[] = $element;
    }
}

// $sqlArray will look like: ["(?,?,?)", "(?,?,?)", ... ]

// Your $paramArray will basically be a flattened version of $rows.

$sql .= implode(',', $sqlArray);

$stmt = $db->prepare($sql);

$stmt->execute($paramArray);

This approach combines multiple row insertions into a single prepared statement and execute operation. It reduces overhead by eliminating the need for individual statement preparation and execution for each row.

Performance Comparison

While the batched row insertion approach theoretically provides performance benefits, the practical difference can be negligible for smaller datasets. However, for large datasets or in scenarios where performance is critical, the batched approach should be considered.

Security Considerations

Both approaches use parameterized queries, which help prevent SQL injection by treating values as data rather than commands. However, the batched approach requires more careful handling of the parameter array to ensure proper mapping to the SQL statement.

Conclusion

The best way to insert multiple rows in PHP PDO MySQL depends on the specific requirements of your application. For smaller datasets or scenarios where performance is not a primary concern, the individual row insertion approach might suffice. For larger datasets or in performance-critical situations, the batched row insertion approach offers improved efficiency. However, it requires careful consideration of security measures to prevent potential vulnerabilities.