$conn = mysqli_connect('127.0.0.1', 'root', '111111') or die(mysqli_error());
mysqli_select_db($conn, 'mraz');
mysqli_query($conn, 'BEGIN');
$rs = mysqli_query($conn, 'SELECT count(*) as total FROM test WHERE username = "mraz" FOR UPDATE');
$row = mysqli_fetch_array($rs);
if($row['total']>0){
exit('exist');
}
mysqli_query($conn, "insert into test(username) values ('mraz')");
var_dump('error:'.mysqli_errno($conn));
$insert_id = mysqli_insert_id($conn);
mysqli_query($conn, 'COMMIT');
echo 'insert_id:'.$insert_id.'
';
mysqli_free_result($rs);
mysqli_close($conn);
上面这段代码,为什么事件写在begin和commit之间,就可以一荣俱荣,唇亡齿寒了呢?
这是一个新入行的程序员问的,望大神解答。。。。。