Question

我在尝试使用代码时遇到此错误：

警告：mysqli_query（）期望参数1为mysqli，给定字符串   在第23行的D：\ AppServ \ www \ my \ classes \ db.class.php

警告：mysqli_error（）期望参数1为mysqli，null给定   在第23行的D：\ AppServ \ www \ my \ classes \ db.class.php

db.class.php文件：

class DBclass{
    private $servername;
    private $username;
    private $password;
    private $dbname;
    private $connect;

    public function connectDB(){

        $this->connect = mysqli_connect($this->servername,$this->username,$this->password,$this->dbname);

        if(!$this->connect){
            echo 'Error : Fail to connect to database !!' . mysqli_error($this->connect);
        }
    }
    public function selectTBL($colum,$from,$where = '',$value = ''){
        if($where == '' && $value == ''){
            $query = 'SELECT '.$colum.'FROM '.$from;
        }elseif($where != '' && $value != ''){
            $query = 'SELECT '.$colum.'FROM '.$from.' WHERE '.$where. ' = '.$value;
        }
        mysqli_query($query,$this->connect) or die(mysqli_error($this->connect));
        $row = mysqli_fetch_array($query);
        return $row[$colum];
    }
}

home.html文件：

<?php  $query = new DBclass; ?>
<html dir="rtl">
    <head>
        <title>title</title>
    </head>
    <body>
        <?php $query->selectTBL('VALUE','SITE_CONFIGS','CONFIG','SITE_TITLE'); ?>
    </body>
</html>

Answer 1

    public function selectTBL($colum,$from,$where = '',$value = '')
    {
        if( is_null($this->connect))
            $this->connectDB();

        if($where == '' && $value == ''){
            $query = 'SELECT '.$colum.'FROM '.$from;
        }elseif($where != '' && $value != ''){
            $query = 'SELECT '.$colum.'FROM '.$from.' WHERE '.$where. ' = '.$value;
        }
        $result = mysqli_query($this->connect, $query) or die(mysqli_error($this->connect));
        $row = mysqli_fetch_array($result);
        return $row[$colum];
    }

警告：mysqli_query（）期望参数1为mysqli

1 个答案: