php - mysqli_query() 期望参数 1 为 mysqli，字符串给出

Question

这是我的 php 文件

<?php

/*
 * Following code will create a new product row
 * All product details are read from HTTP Post Request
 */
// array for JSON response
$response = array();

// check for required fields
if (isset($_POST['userName']) && isset($_POST['userContact']) && isset($_POST['userAddress']) && isset($_POST['userStore']) && isset($_POST['userRequest'])) {

    $userName = $_POST['userName'];
    $userContact = $_POST['userContact'];
    $userAddress = $_POST['userAddress'];
    $userStore = $_POST['userStore'];
    $userRequest = $_POST['userRequest'];

    // include db connect class
    require_once __DIR__ . '/db_connect.php';

    // connecting to db
    $db = new DB_CONNECT();


    // mysql inserting a new row
    $result = "INSERT INTO userrequests(userName, contactNumber, userAddress, storeList, requestBody) VALUES('$userName', '$userContact', '$userAddress', '$userStore', '$userRequest')";


    // check if row inserted or not
    if (mysqli_query($result,$db)) {
        // successfully inserted into database
        $response["success"] = 1;
        $response["message"] = "Product successfully created.";

        // echoing JSON response
        echo json_encode($response);
        echo $result;
    } else {
        // failed to insert row
        $response["success"] = 0;
        $response["message"] = "IsitdispllayingthusOops! An error occurred.";

        // echoing JSON response
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";

    // echoing JSON response
    echo json_encode($response);
}
?>

这是我的 db_connect.php

<?php 
    /**
 * A class file to connect to database
 */
class DB_CONNECT {

    // constructor
    function __construct() {
        // connecting to database
        $this->connect();
    }

    // destructor
    function __destruct() {
        // closing db connection
        $this->close();
    }

    /**
     * Function to connect with database
     */
    function connect() {
        // import database connection variables
        require_once __DIR__ . '/db_config.php';

        // Connecting to mysql database
        $con = mysqli_connect(DB_SERVER, DB_USER, DB_PASSWORD, DB_DATABASE) or die(mysqli_error());

        // Selecing database
        $db = mysqli_select_db($con,DB_DATABASE) or die(mysqli_error()) or die(mysqli_error());

        // returing connection cursor
        return $con;
    }

    /**
     * Function to close db connection
     */
    function close() {
        // closing db connection

    }

}



?>

我的代码似乎有问题，这是我得到的错误mysqli_query() 期望参数 1 为 mysqli，给出的字符串。有人知道如何解决这个问题吗？我已经通过 StackOverFlow 搜索了这方面的内容并尝试了所有解决方案，但仍然无法解决。

Answer 1

修改您的数据库连接类以维护连接:

class DB_CONNECT {

    protected $connection = null;    

    // constructor
    function __construct() {
        // connecting to database
        $this->connection = $this->connect();
    }

    // destructor
    function __destruct() {
        // closing db connection
        $this->close();
    }

    /**
     * Function to connect with database
     */
    function connect() {
        // import database connection variables
        require_once __DIR__ . '/db_config.php';

        // Connecting to mysql database
        $con = mysqli_connect(DB_SERVER, DB_USER, DB_PASSWORD, DB_DATABASE) or die(mysqli_error());

        // Selecing database
        $db = mysqli_select_db($con,DB_DATABASE) or die(mysqli_error()) or die(mysqli_error());

        // returing connection cursor
        return $con;
    }

    public function getConnection() {
        return $this->connection;
    }

    /**
     * Function to close db connection
     */
    function close() {
        // closing db connection

    }

}

然后将查询行修改为:

if (mysqli_query($db->getConnection(), $result)) {