php mysql_num_rows PHP mysqli_rollback() 函数

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// Set autocommit to off
mysqli_autocommit($con,FALSE);

// Insert some values
mysqli_query($con,"INSERT INTO Persons (FirstName,LastName,Age)
VALUES ('Peter','Griffin',35)");
mysqli_query($con,"INSERT INTO Persons (FirstName,LastName,Age)
VALUES ('Glenn','Quagmire',33)");

// Commit transaction
mysqli_commit($con);

// Rollback transaction
mysqli_rollback($con);

// Close connection
mysqli_close($con);
?>