Can PDO_MYSQLND Execute Multiple Queries in a Single Statement?

PDO Support for Multiple Queries: PDO_MYSQLND

PDO traditionally does not allow multiple queries in a single statement. However, two PDO drivers, PDO_MYSQL and PDO_MYSQLND, introduced support for this functionality.

PDO_MYSQLND: The Default MySQL Driver

PDO_MYSQLND replaced PDO_MYSQL in PHP 5.3, and it is now the default MySQL driver for PDO. It provides support for multiple queries, but with the limitation that the queries must use constant values rather than data supplied from PHP variables.

Using exec for Multiple Queries

To execute multiple queries using PDO_MYSQLND with exec, follow these steps:

1. Ensure PHP 5.3 and MySQLND are installed.
2. Set the PDO::ATTR_EMULATE_PREPARES attribute to 0 if you want to use native prepared statements or 1 if you prefer emulated prepared statements.
3. Use the exec() method to execute the SQL queries separated by semicolons.
4. Note that this method is suitable for queries with constant values only.

Using Prepared Statements for Multiple Queries

If you need to use data from PHP variables, you will need to use prepared statements:

1. Ensure PHP 5.3 and MySQLND are installed.
2. Set the PDO::ATTR_EMULATE_PREPARES attribute to 1 if you want to use emulated prepared statements (default for MySQL).
3. Prepare the statement with the multiple SQL queries.
4. Execute the prepared statement with the parameters bound using the execute() method.
5. Loop over the result sets using the nextRowset() method to check for errors or collect results.

Encoding Considerations

When using emulated prepared statements, ensure that the encoding specified in the DSN matches the actual data encoding to prevent potential SQL injection vulnerabilities.

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