php 在非对象上调用成员函数 query()
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Call to a member function query() on a non-object
提问by Sinan Samet
I get this error:
我收到此错误：
Call to a member function query() on a non-object.
在非对象上调用成员函数 query()。
Also when I use other MySQLi functions it gives me the same error but for that function.
此外，当我使用其他 MySQLi 函数时，它会给我同样的错误，但对于该函数。
My connection.php:
我的connection.php：
<?php
$mysqli = new mysqli("localhost","user","pass","db");
if(mysqli_connect_errno()){
trigger_error('Connection failed: '.$mysqli->error);
}
?>
My function:
我的功能：
function form_year($find, $value, $from, $vehicletype){
//Query setup
$autoquery = "SELECT
Year,
Vehicle,
Brand,
Model,
Type,
FROM
vehicle_tbl
WHERE
Vehicle = '".$vehicletype."'
GROUP BY
Year";
$autoresult = $mysqli->query($autoquery);
$search = array("%value%", "%options%");
$rows = file_get_contents("tpl/options.html");
while($row = $autoresult->fetch_assoc()){
$replace = array($row[$value], $row[$value]);
$tr .= str_replace($search, $replace, $rows);
}
return str_replace($find, $tr, $from);
}
Function and connection is included where the function is called
函数和连接包含在调用函数的地方
回答by Green Black
Quick/dirty fix:
快速/脏修复：
function form_year($find, $value, $from, $vehicletype){
//Query setup
global $mysqli;
$autoquery = "SELECT [...]
回答by Mike Brant
Your $mysqliobject is in global scope, not in the scope of the function. You should pass the mysqliobject to the function as a parameter such that you have access to it. So something like this:
您的$mysqli对象在全局范围内，而不是在函数范围内。您应该将mysqli对象作为参数传递给函数，以便您可以访问它。所以像这样：
function form_year($find, $value, $from, $vehicletype, $db){
...
$autoresult = $db->query($autoquery);
...
}
Note I would also add some validation in the function to make sure a proper mysqli object was passed, but that is not shown.
注意我还会在函数中添加一些验证以确保传递了正确的 mysqli 对象，但未显示。
回答by Samuel Teuber
You might want to try to delete the comma after Typeas this might be a syntax error for the MySQL string. Also try to echo $mysqli->errorand look what it says.
您可能想尝试删除逗号，Type因为这可能是 MySQL 字符串的语法错误。也试着回声$mysqli->error看看它说了什么。
回答by Rosme
You got to make sure that your $mysqli is available in scope(which is not the case in your function). A few solution available: global, passing in arguments, singleton. Personnaly I usually do singleton for my database connection, something like that:
您必须确保您的 $mysqli 在范围内可用（在您的函数中并非如此）。一些可用的解决方案：全局、传入参数、单例。我个人通常为我的数据库连接做单例，就像这样：
class DB {
private static $_instance;
public static function get() {
if(!isset(self::$_instance)) {
self::$_instance = new mysqli("localhost","user","pass","db");
if(mysqli_connect_errno()) {
trigger_error('Connection failed: '.self::$_instance->error);
}
}
return self::$_instance;
}
}
//Calling
$autoresult = DB::get()->query($autoquery);
