dtbl1231 2010-10-27 21:42
浏览 114
已采纳

PHP致命错误:在非对象上调用成员函数execute()

I get the error PHP Fatal error: Call to a member function execute() on a non-object refering to the ....->execute() line whenever I call something like

$select_str = 'select id, stamp, lat, lng, spd from gps';
$select = $db->prepare($select_str);
$select->execute();

or

$insert = $db->prepare('insert into gps (id, lat, lng, spd) values (?, ?, ?, ?)');
$insert->execute(array($id, $lat, $lng, $spd));

From searching on the net I suspect that $select (or $insert) is somehow becoming a "dead object" which holds the data, but on which methods can't be called.

But I don't know how to prevent it and my PHP experience is very short (I'm coming from Perl land). Please help me to fix this, it is probably something minor.

And below is my complete script, I think (I hope) it is quite readable - it lets you create a table, insert a record, delete records, view them or drop the table again - all depending on the $_REQUEST['mode'] parameter:

<?php

@define('DBHOST', 'localhost');
@define('DBNAME', 'snake');
@define('DBUSER', 'snake');
@define('DBPASS', 'snake');

# lowercase mode and id parameters; replace commas by dots in lat, lng, spd
$mode   = isset($_REQUEST['mode']) ? strtolower(trim($_REQUEST['mode']))     : '';
$id     = isset($_REQUEST['id'])   ? strtolower(trim($_REQUEST['id']))       : '';
$lat    = isset($_REQUEST['lat'])  ? strtr(trim($_REQUEST['lat']), ',', '.') : '';
$lng    = isset($_REQUEST['lng'])  ? strtr(trim($_REQUEST['lng']), ',', '.') : '';
$spd    = isset($_REQUEST['spd'])  ? strtr(trim($_REQUEST['spd']), ',', '.') : '';

# id must be 32 chars long hex number; lat, lng, spd must be decimal numbers
$id_ok  = preg_match('/^[a-f0-9]{32}$/', $id);
$lat_ok = preg_match('/^[+-]?[0-9.]+$/', $lat);
$lng_ok = preg_match('/^[+-]?[0-9.]+$/', $lng);
$spd_ok = preg_match('/^\+?[0-9.]+$/', $spd);

# has the user selected a mode and provided valid input?
$create_ok = ($mode == 'create');
$insert_ok = ($mode == 'insert' && $id_ok && $lat_ok && $lng_ok && $spd_ok);
$delete_ok = ($mode == 'delete' && $id_ok);
$select_ok = ($mode == 'select');
$drop_ok   = ($mode == 'drop');

# first call or invalid input: display web form and exit
if (!($create_ok || $insert_ok || $delete_ok || $select_ok || $drop_ok)) {
        header('Content-Type: text/html; charset=utf-8');
        print '<html>
<body>
<form method="post">
<p>Mode:<br />
<input type="radio" name="mode" value="create"><i>create table</i><br />
<input type="radio" name="mode" value="select" checked>select records (can specify id)<br />
<input type="radio" name="mode" value="insert">insert 1 record (must specify all)<br />
<input type="radio" name="mode" value="delete">delete records (must specify id)<br />
<input type="radio" name="mode" value="drop"><i>drop table</i><br />
</p>
<p>Id: <input type="text" name="id" size=32 maxlength=32 /> (32 hex chars)</p>
<p>Latitude: <input type="text" name="lat" size=10 /> (between -90 and 90)</p>
<p>Longitude: <input type="text" name="lng" size=10 /> (between -90 and 90)</p>
<p>Speed: <input type="text" name="spd" size=10 /> (not negative)</p>
<p><input type="submit" value="OK" /></p>
</form>
</body>
</html>
';
        exit();
}
try {
        # enable persistent connections and throw exception on any errors
        $options = array(PDO::ATTR_ERRMODE    => PDO::ERRMODE_EXCEPTION,
                         PDO::ATTR_PERSISTENT => true);
        $db = new PDO('mysql:host=' . DBHOST . '; dbname=' . DBNAME, DBUSER, DBPASS, $options);

        if ($create_ok) {
                $db->exec('create table gps (
                                id char(32) not null check length(id)=32,
                                lat decimal(5,3) not null,
                                lgt decimal(5,3) not null,
                                spd decimal(5,3) unsigned not null,
                                stamp timestamp default now(),
                                index(id) )');
        } else if ($insert_ok) {
                $insert = $db->prepare('insert into gps (id, lat, lng, spd) values (?, ?, ?, ?)');
                $insert->execute(array($id, $lat, $lng, $spd));
        } else if ($delete_ok) {
        } else if ($drop_ok) {
                $db->exec('drop table gps');
                header('Content-Type: text/plain');
                print('Database dropped');
                exit();
        }

        # display current table content in XML format
        $select_str = 'select id, stamp, lat, lng, spd from gps';
        # but filter by id if requested by user
        if ($select_ok && $id_ok) {
                $select = $db->prepare($select_str . ' where id = ?');
                $select->execute(array($id));
        } else {
                $select = $db->prepare($select_str);
                $select->execute();
        }

        header('Content-Type: text/xml; charset=utf-8');
        print('<?xml version="1.0"?><gps>');
        while ($row = $select->fetch(PDO::FETCH_ASSOC)) {
                printf('<pos id="%s" stamp="%u" lat="%f" lng="%f" spd="%f" />',
                    $row['id'], $row['stamp'], $row['lat'], $row['lng'], $row['spd']);
        }
        print('</gps>');
} catch (Exception $e) {
        header('Content-Type: text/plain');
        print('Database problem: ' . $e->getMessage());
}

?>

And the MySQL user 'snake' has these permissions:

select * from mysql.user where User='snake';
+-----------+-------+------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+
| Host      | User  | Password         | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections |
+-----------+-------+------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+
| localhost | snake | 684bce5059b3e0a8 | Y           | Y           | N           | Y           | Y           | Y         | N           | N             | N            | N         | N          | N               | Y          | N          | N            | N          | N                     | N                | N            | N               | N                | N                | N              | N                   | N                  | N                |          |            |             |              |             0 |           0 |               0 |                    0 |
+-----------+-------+------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+

Thank you! Alex

  • 写回答

1条回答 默认 最新

  • doucheyi1347 2010-10-27 21:48
    关注

    The key is the behaviour of PDO::prepare():

    If the database server successfully prepares the statement, PDO::prepare() returns a PDOStatement object. If the database server cannot successfully prepare the statement, PDO::prepare() returns FALSE or emits PDOException (depending on error handling).

    prepare() is somehow failing with your query.

    By default, PDO is mute and does not throw any error messages. See this page to see how to make PDO show errors, and details about what goes wrong.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 关于#linux#的问题(输入输出错误):出现这个界面接着我重新装系统,又让修电脑的师傅帮我扫描硬盘(没有问题)用着用着又卡死(相关搜索:固态硬盘)
  • ¥15 cv::resize不同线程时间不同
  • ¥15 web课程,怎么做啊😭没好好听课 根本不知道怎么下手
  • ¥15 做一个关于单片机的比较难的代码,然后搞一个PPT进行解释
  • ¥15 python提取.csv文件中的链接会经常出现爬取失败
  • ¥15 数据结构中的数组地址问题
  • ¥15 maya的mel里,怎样先选择模型A,然后利用mel脚本自动选择有相同名字的模型B呢。
  • ¥15 Python题,根本不会啊
  • ¥15 会会信号与系统和python的来
  • ¥15 关于#python#的问题