重复 php 函数

Question

我的代码有问题。它总是重复输入。这是我的函数：

public function insert()
    {           
        $con=mysqli_connect("127.0.0.1","root","","dbms_project");
        if (!$con)
          {
          die('Could not connect: ' . mysql_error());
          }
        $sql="INSERT INTO customers (First_Name,Last_Name,Address,Phone)
                VALUES
        ('{$_POST['first_name']}','{$_POST['last_name']}','{$_POST['address']}','{$_POST['phone']}')";
        mysqli_query($con, $sql);
        if (!mysqli_query($con,$sql))
          {

          //redirect('home/customer');

          }
          $this->load->view('customer_view');
        mysqli_close($con);
    }

这是网站中的代码。我还尝试存储下一个值以将其用作 customer_id:

的值

             //using insert function
             <form action ="<?= site_url('home/insert')?>" class="formInsert" method="post">
             <td><button class="btn btn-xs btn-primary btn-block" type="submit" value="Login">+</button></td>
             <td>
             //i'm trying to put the output and use it to be the value of the customer id
             <?php $con=mysqli_connect("127.0.0.1","root","","dbms_project");
                // Check connection
                    if (mysqli_connect_errno())
                    {
                    echo "Failed to connect to MySQL: " . mysqli_connect_error();
                    }
                $result = mysqli_query($con,"SELECT max(Customer_ID) FROM customers");
                $lastvalue = mysqli_fetch_row($result);
                $resultlastvalue = $lastvalue[0] + 1;
                echo  " ". $resultlastvalue . " " ;?>
                </td>
             <td><input type="text" class="form-control" name="first_name" placeholder="First Name" required maxlength="40" autofocus /></td>
             <td><input type="text" class="form-control" name="last_name" placeholder="Last Name" required maxlength="40" autofocus /></td>          
             <td><input type="text" class="form-control" name="address" placeholder="Address" required maxlength="40" autofocus /></td>          
             <td><input type="text" class="form-control" name="phone" placeholder="Phone" required maxlength="40" autofocus /></td>          
             </form>

每次我刷新页面时，它都会复制重复的值。

Answer 1

这将始终在页面刷新时插入重复记录。你需要稍微改变一下逻辑。

取名字、姓氏和phone三个变量
连接到数据库
使用 SELECT 查询
如果是，请不要运行 INSERT 查询
如果没有，插入

我们需要这样的东西

$select = " SELECT * FROM customers WHERE First_Name = '$_POST['first_name']' AND Last_Name = '$_POST['last_name']' AND Phone = '$_POST['phone']' ";
 $query = mysqli_query($select);

if(mysqli_num_rows($query) > 0){

                echo "User already exists";
                                  }
    else {
        $sql="INSERT INTO customers (First_Name,Last_Name,Address,Phone)
            VALUES ('{$_POST['first_name']}','{$_POST['last_name']}','{$_POST['address']}','{$_POST['phone']}')";
         }

重复 php 函数

Duplicates php function

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