insert json associative array into mysql

Question

I have been looking for how to inserting multiple key->value into mysql - database. I can insert single objects, but not in an foreach-loop i must be doing something wrong. Considering i know my java code works, hence I am able to store individual objects in a singe-coloumn table in the database, it must be my php-syntax that is wrong - even though I follow a tutorial. please help me Here is my php-code, which must have the error

<?php

    require_once 'db.php';
  $json = file_get_contents('php://input');
  $obj = json_decode($json,true);





  $st = mysqli_prepare($con, 'INSERT INTO movies(title,year,genre,director) VALUES(?,?,?,?)');

  mysqli_stmt_bind_param($st, 'sdss', $title, $year, $genre, $director);


  foreach ($obj as $row){
  $title =  $obj['title'];
  $year =  $obj['year'];
  $genre =  $obj['genre'];
  $director =  $obj['director'];   

  mysqli_stmt_execute($st);

  }


  ?>

my require_once 'db_php'; connects to the database, and i get the data from a remote java application. Here is my javacode - just leaving out my database-URL, and method-creation

    HttpURLConnection connection= null;
    try {

        URL obj = new URL(url2);
         connection = (HttpURLConnection) obj.openConnection();
        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
    //  connection.setRequestProperty("Accept", "application/json");
        connection.connect();


        OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());   
        JSONObject request = new JSONObject();
        request.put("action","login");
        request.put("title","The 40 year old virgin");
        request.put("year","2004");
        request.put("genre","Horror");
        request.put("director","Takashi Shimizu");




        String output =request.toString();                                             
        writer.write(output);                                                           
        writer.flush();                                                                 
        writer.close();   


        InputStream input = connection.getInputStream();                                    
        BufferedReader reader = new BufferedReader(new InputStreamReader(input));       
        StringBuilder result = new StringBuilder();                                     
        String line;       

        int responseCode = connection.getResponseCode();
        System.out.println("ResponseCode: " + responseCode);


        while ((line = reader.readLine()) != null) {                                    
            result.append(line);                                                        
        }         

        System.out.println("result:" + result.toString());
    }


   catch (IOException e) {                                                           

    } finally {   

        connection.disconnect();

    }       
} 

And this is the error I get in the console in IDE - eclipse ":Warning: mysqli_stmt_bind_param() expects parameter 1 to be mysqli_stmt" however, I don´t know what to do with it

Answer 1

If the sql failed the $st won't be a mysqli statement object, I normally use mysqli as an object and any typos in the statement usually show up as an error calling bind param on a non object, I suspect you may have a similar issue. You can test for errors with a procedural style some thing like this:

if($st == false){
    error_log(mysqli_error($conn));
}

mysqli_prepare returns false if the prepare fails, then you can call mysqli_error passing in the mysqli_connection to get the details of the last error.