将PHP连接到MYSQL时mysqli_error（）

Question

我知道有很多与此相关的问题，但我无法用我的代码找到问题。

以下是我的PHP代码：

$model = new LoginForm();
     if(isset(Yii::$app->user->isGuest)){
          return $this->render('login', [
                   'model' => $model,//Model is the user active record
                 ]);//render the view file located in **site folder** login.php **view file**
     }
    $model = Users::findOne(yii::$app->user->id);//model is the users model used to display controls in index.php view
    return $this->render('/site/index', ['model' => $model]);

昨天我运行时代码完全正常。

以下是MYSQL表的详细信息：

运行代码时出现以下错误：

<?php
//set the connection variables
$hostname = "localhost";
$username = "root";
$password = "password";
$database = "fyp";
$filename = "C:/scripts/nea.csv";

//connect to mysql database
$myConnection = mysqli_connect($hostname, $username, $password, $database)  
or die("Error " . mysqli_error($myConnection));

// open the csv file
$fp = fopen($filename,"r");

//parse the csv file row by row
while(($row = fgetcsv($fp,"500",",")) != FALSE)
{
 //insert csv data into mysql table
    $sql = "INSERT INTO neaweather (ValidTime, Date, Time, Lat, Lon, AreaName) VALUES ( '".mysql_escape_string($row[0])."','".mysql_escape_string($row[1])."','".mysql_escape_string($row[2])."','".mysql_escape_string($row[3])."','".mysql_escape_string($row[4])."','".mysql_escape_string($row[5])."')";
    $query = mysqli_query($myConnection,$sql);
    if($query){
        echo "row inserted\n";
    }
    else{
        echo die(mysql_error());
    }
}
fclose($fp);

//close the db connection
mysqli_close($myConnection);

?>

这是代码的第10行：

C:\scripts>php neaweather.php
PHP Warning:  mysqli_connect(): (HY000/2002): No connection could be made   
because the target machine actively refused it.in C:\scripts\neaweather.php  
on line 10

Warning: mysqli_connect(): (HY000/2002): No connection could be made because 
the target machine actively refused it. in C:\scripts\neaweather.php on line  
10

PHP Warning:  mysqli_error() expects parameter 1 to be mysqli, boolean given  
in C:\scripts\neaweather.php on line 10

Warning: mysqli_error() expects parameter 1 to be mysqli, boolean given in   
C:\scripts\neaweather.php on line 10 
Error

Answer 1

您的屏幕截图显示您的mysql服务器正在端口3307上运行。默认情况下使用3306。 你需要替换它：

$myConnection = mysqli_connect($hostname, $username, $password, $database) or die("Error " . mysqli_error($myConnection));

有了这个：

$myConnection = mysqli_connect($hostname, $username, $password, $database, 3307) or die("Error " . mysqli_error($myConnection));

Answer 2

MySQL的默认端口是3306.在你的mysql客户端中你使用3307.也许你必须在php应用程序中设置端口。

myConnection = mysqli_connect($hostname, $username, $password, $database, 3307) 
    or die("Error " . mysqli_error($myConnection));

Answer 3

在mysqli_connect中包含端口，因为如果不提供则需要3306

mysqli_connect(host,username,password,dbname,port);

Answer 4

关于这一点：

  

PHP警告：mysqli_error（）期望参数1为mysqli，boolean   在第10行的C：\ scripts \ neaweather.php中给出

...这是因为您错误地获取了连接错误。当mysqli_connect()失败时，它不返回资源（用于什么？）但是false因此mysqli_error($myConnection)（期望资源）失败。 PHP manual page中有一个具有正确机制的示例：

$link = mysqli_connect("127.0.0.1", "my_user", "my_password", "my_db");
if (!$link) {
    echo "Error: Unable to connect to MySQL." . PHP_EOL;
    echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
    echo "Debugging error: " . mysqli_connect_error() . PHP_EOL;
    exit;
}