如何在PHP中修复未定义的变量 [英] How to fix a undefined variable in PHP

问题描述

嗨

我试图在我的数据库中插入和显示图像，但在插入文件中我收到此错误



是无论如何，我可以解决这个问题。有人能指出我的方向。我不是要求任何人做这个任务只是寻找一些解释和一些解决方案。这是错误

注意：未定义的变量： C中的img_id  ：\ wamp64 \过网址 15 <\\ _ spanana_itec244 \\\ npp \ upload.php  

这就是我的尝试。



我尝试了什么：

 <   pre  >  <？ php 
 
 session_start（）; 
 
 if（isset（$ _ POST ['  submit']））
 {
 
 $ db_host = '  localhost'; 
 $ db_username = '  root'; 
 $ db_password =  ; 
 
 $ con = mysqli_connect（$ db_host，$ db_username，$ db_password）或 die（mysqli_connect_error（））; 
 
 mysqli_select_db（$ con，'  food'）或 die（mysqli_error（$ con））; 
 $ sql =   SELECT * FROM tbl_images WHERE img_id ='$ img_id'; 
 $ result = mysqli_query（$ con，$ sql）或 die（ 错误： .mysqli_error（$ con））; 
 $ rowcount = mysqli_num_rows（$ result）; 
 
 if（$ rowcount> = 1）
 {
  echo   < script type = \text / javascript \; 
 alert（'files not uploaded'）; 
 window。 location = \login.html \; 
< / script>; 
} 
 其他 
 {
  //  < span class =code-comment>将图像插入表中 
 
  $ sql  =   INSERT INTO tbl_images 
 VALUES（'img_id'，'name'，'image'）; 
 
 if（mysqli_query（$ con，$ sql））
 {
 mysqli_close（$ con）; 
 header（  location：dashboard.php）; 
} 
 其他 
 {
  echo   插入图像时出错; 
} 
} 
} 
 
 
 ？>  

解决方案

_POST [' submit']））
{

db_host = ' localhost';

db_username = ' root';

hi
I am trying to insert and display images in my database but in the insert file I am getting this error

is there anyway that i can fix this. can some one point me in the direction. i am not asking no one to do this assignment just looking for some explaining and some resolution to it. this is the error

Notice: Undefined variable: img_id in C:\wamp64\www\luana_itec244\php\upload.php on line 15

this is what I have tried.

What I have tried:

<pre><?php

		session_start();
		
	if(isset($_POST['submit']))
	{

		$db_host='localhost';
		$db_username='root';
		$db_password="";
		
		$con=mysqli_connect($db_host,$db_username,$db_password) or die(mysqli_connect_error());
		
			mysqli_select_db($con, 'food') or die(mysqli_error($con));
			$sql="SELECT * FROM tbl_images WHERE img_id='$img_id'";
			$result=mysqli_query($con, $sql) or die("Error:" .mysqli_error($con));
			$rowcount=mysqli_num_rows($result);
			
			if($rowcount >=1)
			{
				echo"<script type=\"text/javascript\";
						alert('files not uploaded');
						window.location=\"login.html\";
					</script>";
			}
				else
				{
					//insert images into table
					
					$sql = "INSERT INTO tbl_images
					VALUES('img_id','name','image')";
				
					if(mysqli_query($con, $sql))
					{
						mysqli_close($con);
						header("location:dashboard.php");
					}
					else
					{
						echo "Error inserting images";
					}
				}
	}
	
	
?>

解决方案

_POST['submit'])) {

db_host='localhost';

db_username='root';

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