Question

//function to add bm 
function add_bm($new_url, $email) 
{ 
    $db = $this->dbm; 


    $this->new_url = $new_url; 
    $this->email = $email; 

    $sql = "select * from bookmark where email='$this->valid_user' and bm_URL='$this->new_url'"; 

    if(!$stmt = $db->conn->query($sql)) 
     { 

      echo "query failed: (" . $db->conn->errno . ") " .$db->conn->error; 
     }else{ 
     //echo "can check"; 
     //return true; 


    //row count 
    if($stmt->num_rows > 0){ 
     echo "<b><br>Sorry ! <br> The URL had already been added . </b> "; 
     return false; 
     }else{ 
    //return true; 

    // prepare and bind 

     $stmt = $db->conn->prepare("INSERT INTO bookmark (email, bm_URL,) VALUES (?,?)"); 
     $stmt->bind_param("ss", $this->email, $this->new_url); 


// set parameters and execute 
    if($stmt->execute()){ 

      $stmt->close(); 
     $db->conn->close(); 

     return true; 
      } 
     } 
     } 

} 

Answer 1

當你這樣做DB操作，檢查錯誤，然後再繼續。否則你會得到意想不到的行爲和令人費解的錯誤，如這樣。

您的$stmt->bind_param不起作用，因爲$stmt===false因爲前面的指令出錯了。

if(!$stmt = $db->conn->prepare("INSERT INTO ...")){ 
    //something went wrong. This shows the error but handle as appropriate 
    die($db->$conn->error); 
} 
//safe to continue 
$stmt->bind_param(...)