PHP_数据库_PDO查询操作和预编译语句操作。

PDO使用dns进行连接，我采用new ClassName()方式（其实大同小异，形式罢了）。

尝试先插入，然后查询，在查询遍历每一条的时候插入。
结果很简单，第一次插入能插入，但是在遍历结束之前是不能插入的。

 1 <?php
 2 $dsn = 'mysql:dbname=stuphp;host=127.0.0.1';
 3 $user = 'root';
 4 $password = 'admin';
 5 
 6 try {
 7     $dbh = new PDO ( $dsn, $user, $password );
 8 } catch ( PDOException $e ) {
 9     echo 'Connection failed: ' . $e->getMessage ();
10 }
11 $dbh->query ( 'set names utf8' ); // 是我的mysql数据库也是utf8编码的 。但是就是不行。必须这么写才行。
12 
13 //插入一条记录
14 $username = 'leaves';
15 $password = 's&^*&B324';
16 $mark = '我是好人';
17 $pstmt = $dbh->prepare ( 'INSERT INTO TUSER(USERNAME,PASSWORD,MARK) VALUES(:username,:password,:mark)' );
18 $pstmt->bindParam ( ':username', $username );
19 $pstmt->bindParam ( ':password', $password );
20 $pstmt->bindParam ( ':mark', $mark );
21 $pstmt->execute ();
22 print_r ( $pstmt->errorInfo () );
23 
24 $sql = 'SELECT USERNAME,PASSWORD,MARK FROM TUSER';
25 $result = $dbh->query ( $sql );
26 
27 $row = $result->fetchObject ();
28 $dbh->beginTransaction();
29 while ( $row ) {
30     $username = $row->USERNAME;
31     $password = $row->PASSWORD;
32     $mark = $row->MARK;
33     
34     echo $username . "\t";
35     echo $password . "\t";
36     echo $mark . "<br/>";
37     
38     
39     //------------------中途尝试插入
40     $pstmt = $dbh->prepare ( 'INSERT INTO TU22SER(USERNAME,PASSWORD,MARK) VALUES(:username,:password,:mark)' );
41     $pstmt->bindParam ( ':username', $username );
42     $pstmt->bindParam ( ':password', $password );
43     $pstmt->bindParam ( ':mark', $mark );
44     $pstmt->execute ();
45     print_r ( $pstmt->errorInfo () );
46     //上面的查询不会成功。原因是在查询没有结束的时候不允许你继续插入，就好像别人在存钱，你在取钱一样。
47     //下面是异常信息
48     /*
49      * Array ( [0] => HY000 [1] => 2014 [2] => Cannot execute queries while
50      * other unbuffered queries are active. Consider using
51      * PDOStatement::fetchAll(). Alternatively, if your code is only ever going
52      * to run against mysql, you may enable query buffering by setting the
53      * PDO_MYSQL_ATTR_USE_BUFFERED_QUERY attribute. )
54      */
55     
56     $row = $result->fetchObject ();
57 }
58 
59 
60 //插入一条记录,下面的代码能执行，无错
61 // $username = 'leaves';
62 // $password = 's&^*&B324';
63 // $mark = '我是好人';
64 // $pstmt = $dbh->prepare ( 'INSERT INTO TUSER(USERNAME,PASSWORD,MARK) VALUES(:username,:password,:mark)' );
65 // $pstmt->bindParam ( ':username', $username );
66 // $pstmt->bindParam ( ':password', $password );
67 // $pstmt->bindParam ( ':mark', $mark );
68 // $pstmt->execute ();
69 // print_r ( $pstmt->errorInfo () );
70 ?>

天行健君子以自强不息。