Is there a function for closing a mysql prepared statement with PDO?

问题

In mysqli prepared statements there ismysqli_stmt::close() (Closes a prepared statement):

$stmt->close();

I have searched php.net and the web and cannot find an alternative for PDO.

Is this possible?

And what are the benefits of using it at the end of each of your scripts?

I understand that,

$connection = null;

closes the connection to mysql, but what about closing the query?

回答1:

To free the result set you can apply basic PHP way.

If you are returning the results with PDOStatement::fetchAll() then you would need to unset() the variable to clear it:

$variable = $stmt->fetchAll();

unset($variable);
// or:
$variable = null; 

Or PDOStatement::closeCursor() (Closes the cursor, enabling the statement to be executed again.) may be helpful:

$success = $stmt->closeCursor();

来源：https://stackoverflow.com/questions/5685879/is-there-a-function-for-closing-a-mysql-prepared-statement-with-pdo