Does PDO_MYSQL/PDO_MYSQLND Support Multiple Queries in a Single Statement?

PDO Support for Multiple Queries (PDO_MYSQL, PDO_MYSQLND)

Original Question:

Despite being aware of PDO's lack of support for executing multiple queries in a single statement, concerns have been raised regarding the availability of support for such functionality in PDO_MYSQL and PDO_MYSQLND.

Answer:

Understanding PDO_MYSQL and PDO_MYSQLND:

PDO_MYSQL was depreciated and replaced by PDO_MYSQLND in PHP 5.3. However, the name remains PDO_MYSQL, making it the default driver for MySQL PDO.

Executing Multiple Queries Using PDO:

To execute multiple queries at once, you require the following:

• PHP 5.3 or higher
• MySQLND
• Emulated prepared statements (PDO::ATTR_EMULATE_PREPARES set to 1, which is the default for MySQL)

Using exec:

$sql = "
DELETE FROM car;
INSERT INTO car(name, type) VALUES ('car1', 'coupe');
INSERT INTO car(name, type) VALUES ('car2', 'coupe');
";

$db->exec($sql);

Note: This method is limited to SQL containing constant values.

Using Statements:

$sql = "
DELETE FROM car;
INSERT INTO car(name, type) VALUES (:car1, :type1);
INSERT INTO car(name, type) VALUES (:car2, :type2);
";

$stmt = $db->prepare($sql);
$stmt->execute(
    ["car1" => "brand1", "type1" => "coupe", "car2" => "brand2", "type2" => "coupe"]
);

Loop Over Query Results:

Always remember to loop over query results after executing the statement to check for errors or collect the results.

Note on Emulated Prepared Statements:

• Ensure proper encoding is set in the DSN to avoid potential SQL injection risks.
• Emulate prepared statements may introduce a slight performance penalty.

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