警告:mysqli_query():无法获取 mysqli [英] Warning: mysqli_query(): Couldn't fetch mysqli
问题描述
我遇到了无法从 MySQL 数据库(通过 PHP)检索结果的问题.我在其他地方使用了相同的功能，它完美无缺.但是此时我不断收到警告:mysqli_query():无法获取mysqli"错误.问题的详细信息如下所述.我在我的 PHP 中的其他地方使用了一个非常相似的函数(如下所示的 getAllCountries)，它运行良好:
函数 getAllCountries(){$result = db_query("SELECT countryid, name FROM country ORDER BY name ASC");echo "所以问题如下:
我有一个包含以下代码的 php 文件:
我的functions.php文件有以下一行(连同其他不相关的函数):
require 'dbfunctions.php';我的 dbfunctions.php 看起来像这样:
在我的 PHP 文档中，我调用了以下函数:
if ($userid == -1){showNotAuthorizedPage();} 别的 {myAccountPage();}并且 myAccountPage() 函数与 getUserPicPath() 函数在同一个文件中声明，这个 getUserPicPath() 函数调用如下:
<p><?php getUserPicPath();?></p>我在我的网页上使用标签(http://jqueryui.com/tabs/#default)，那就是我想调用它的地方.myAccountPage() 函数出现以下错误:
Warning: mysqli_query(): 无法在 C:\Users\Dennis\Documents\My Dropbox\xxx\zzz\www\Project Files\includes\dbfunctions.php 中获取 mysqli 第 29 行调用栈# 时间记忆功能位置1 0.0000 256880 {main}() ..\myaccount.php:02 0.0010 283328 myAccountPage() ..\myaccount.php:1813 0.0070 285368 getUserPicPath() ..\myaccount.php:1214 0.0070 285528 db_query() ..\myaccount.php:115 0.0070 285624 mysqli_query () ..\dbfunctions.php:29( ! ) 警告:mysqli_fetch_array() 期望参数 1 为 mysqli_result，在 C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php 中第 13 行给出为空调用栈# 时间记忆功能位置1 0.0000 256880 {main}() ..\myaccount.php:02 0.0010 283328 myAccountPage() ..\myaccount.php:1813 0.0070 285368 getUserPicPath() ..\myaccount.php:1214 0.0080 285768 mysqli_fetch_array () ..\myaccount.php:13( ! ) 注意:未定义变量:第 17 行 C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php 中的图片路径调用栈# 时间记忆功能位置1 0.0000 256880 {main}() ..\myaccount.php:02 0.0010 283328 myAccountPage() ..\myaccount.php:1813 0.0070 285368 getUserPicPath() ..\myaccount.php:121( ! ) 警告:mysqli_close():无法在第 19 行的 C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php 中获取 mysqli调用栈# 时间记忆功能位置1 0.0000 256880 {main}() ..\myaccount.php:02 0.0010 283328 myAccountPage() ..\myaccount.php:1813 0.0070 285368 getUserPicPath() ..\myaccount.php:1214 0.0100 285864 mysqli_close () ..\myaccount.php:19我想是因为你第一次关闭数据库连接的时候，你忘记做了:
unset($connection);然后当您再次尝试连接到数据库时，它会失败，因为它仍然设置为关闭的连接.
I have a problem where I can not retrieve the result from my MySQL database (via PHP). I use the same function in other places and it works flawlessly. However at this point i keep getting the "Warning: mysqli_query(): Couldn't fetch mysqli" error. Details of the problem are explained below. I use a quite similar function elsewhere (getAllCountries as seen below) in my PHP which does work perfectly:
function getAllCountries()
{
$result = db_query("SELECT countryid, name FROM country ORDER BY name ASC");
echo "<select class=addresscountry name=country>";
while($row = mysqli_fetch_array($result)) {
echo '<option value="' . $row['countryid'] . '">' . $row['name'] . '</option>';
}
echo "</select>";
mysqli_close(db_connect());
}
So the problem is the following:
I have a php file containing the following code:
<?php
require 'includes/functions.php';
function getUserPicPath()
{
$userid = $_SESSION['userid'];
$result = db_query("SELECT picture FROM user WHERE userid='$userid'");
while($row = mysqli_fetch_array($result)) {
$picturepath = $row['picture'];
}
echo $picturepath;
mysqli_close(db_connect());
}
my functions.php file has the following line (together with other non-relevant functions):
require 'dbfunctions.php';
and my dbfunctions.php looks like this:
<?php
function db_connect()
{
require ".db_password.php";
static $connection;
if(!isset($connection)) {
$connection = mysqli_connect('localhost',$username,$password,$dbname);
}
if($connection === false) {
return mysqli_connect_error();
}
return $connection;
}
function db_query($query)
{
$connection = db_connect();
$result = mysqli_query($connection,$query);
return $result;
}
In my PHP document I call the following function :
if ($userid == -1)
{
showNotAuthorizedPage();
} else {
myAccountPage();
}
and the myAccountPage() function is declared in the same file as the getUserPicPath() function, this getUserPicPath() function is called as follows:
<div id="tabs-2">
<p><?php getUserPicPath(); ?></p>
</div>
I use the tabs (http://jqueryui.com/tabs/#default) on my webpage and that is where i want to call it in. The myAccountPage() function which gives the following error :
Warning: mysqli_query(): Couldn't fetch mysqli in C:\Users\Dennis\Documents\My Dropbox\xxx\zzz\www\Project Files\includes\dbfunctions.php on line 29
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}( ) ..\myaccount.php:0
2 0.0010 283328 myAccountPage( ) ..\myaccount.php:181
3 0.0070 285368 getUserPicPath( ) ..\myaccount.php:121
4 0.0070 285528 db_query( ) ..\myaccount.php:11
5 0.0070 285624 mysqli_query ( ) ..\dbfunctions.php:29
( ! ) Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, null given in C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php on line 13
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}( ) ..\myaccount.php:0
2 0.0010 283328 myAccountPage( ) ..\myaccount.php:181
3 0.0070 285368 getUserPicPath( ) ..\myaccount.php:121
4 0.0080 285768 mysqli_fetch_array ( ) ..\myaccount.php:13
( ! ) Notice: Undefined variable: picturepath in C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php on line 17
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}( ) ..\myaccount.php:0
2 0.0010 283328 myAccountPage( ) ..\myaccount.php:181
3 0.0070 285368 getUserPicPath( ) ..\myaccount.php:121
( ! ) Warning: mysqli_close(): Couldn't fetch mysqli in C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php on line 19
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}( ) ..\myaccount.php:0
2 0.0010 283328 myAccountPage( ) ..\myaccount.php:181
3 0.0070 285368 getUserPicPath( ) ..\myaccount.php:121
4 0.0100 285864 mysqli_close ( ) ..\myaccount.php:19
I think it is because when you close the database connection the first time, you forget to do:
unset($connection);
And then when you try connecting to the database again, it craps out because it is still set to the closed connection.
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