09 February, 2021

Updating two tables with an inner join

                No comments   

 I am having trouble updating it. I have two tables one is employees and other is attendance.

employees table has fields as (id, employee_id, firstname, lastname, address, email, salary, creacted_on) and attendance table has fields as (id, employee_id, date, time, description). Here is my code for editing.

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<?php
       $query = "SELECT emp.employee_id, emp.firstname, emp.lastname, att.time, att.date, att.description from attendance AS att INNER JOIN employees AS emp where att.employee_id = emp.id";
       $query_run = mysqli_query($connection, $query);
 
       if (mysqli_num_rows($query_run) > 0) {
         while ($row = mysqli_fetch_assoc($query_run)) {
       ?>
           <tr>
             <td><?php echo date('M d, Y', strtotime($row['date'])); ?></td>
             <td><?php echo $row['employee_id']; ?></td>
             <td><?php echo $row['firstname'] . ' ' . $row['lastname']; ?></td>
             <td><?php echo date('h:i A', strtotime($row['time'])); ?></td>
             <td><?php echo ($row['description']) ?></td>
             <td>
               <form action="attendance_edit.php" method="post">
                 <input type="hidden" name="edit_id" value="<?php echo $row['id']; ?>">
                 <button type="submit" name="edit_btn" class='btn btn-success btn-sm edit btn-flat'><i class='fa fa-edit'></i> Edit</button>
               </form>
             </td>
             <td>
               <form action="attendance_code.php" method="post">
                 <input type="hidden" name="deleteattendance_id" value="<?php echo $row['id']; ?>">
                 <button onclick="return  confirm('do you want to delete Y/N')" type="submit" name="deleteattendance_btn" class='btn btn-danger btn-sm delete btn-flat'><i class='fa fa-trash'></i> Delete</button>
                 </form>
                 </td>
               </tr>
 
           <?php


page edit :
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$connection = mysqli_connect("localhost", "root", "", "project08");
           if (isset($_POST['edit_btn'])) {
               $id = $_POST['edit_id'];
               $query = "SELECT * FROM attendance WHERE id= '$id'";
               $result = mysqli_query($connection, $query);
 
               while ($row = mysqli_fetch_assoc($result))
           ?>
 
               <form action="attendance_code.php" method="POST">
 
                   <input type="hidden" name="edit_id" value="<?php echo $row['id'] ?>">
 
                   <div class="form-group">
                       <label> Date </label>
                       <input type="date" name="edit_date" value="<?php echo date('M d, Y', strtotime($row['date'])); ?>" class="form-control datepicker" placeholder="Enter Date">
                   </div>
                   <div class="form-group">
                       <label>Time</label>
                       <input type="time" name="edit_time" value="<?php echo $row['time'] ?>" class="form-control timepicker" placeholder="Enter Time">
                   </div>
                   <div class="form-group">
                       <label>Description</label>
                       <input type="text" name="edit_description" value="<?php echo $row['description'] ?>" class="form-control" placeholder="Enter Description">
                   </div>
 
                   <a href="attendance.php" class="btn btn-danger"> CANCEL </a>
                   <button type="submit" name="update_btn" class="btn btn-primary"> Update </button>
 
               </form>
           <?php


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Hello.

You may want to explain the problem a bit more. You mentioned you have a trouble updating the table for what it seems, however, that was it. It may be hard for somebody to help you - there could be many troubles.
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if (isset($_POST['update_btn'])) {
    $id = $_POST['edit_id'];
    $date = $_POST['edit_date'];
    $time = $_POST['edit_time'];
    $description = $_POST['edit_description'];
 
    $query = "UPDATE attendance att JOIN employees emp ON (att.employee_id = emp.employee_id) SET date = '$date', time = '$time', description = '$description' WHERE id = '$id'";
 
    $query_run = mysqli_query($connection, $query);
 
    if ($query_run) {
        $_SESSION['status'] = "Your data is Updated";
        $_SESSION['status_code'] = "success";
        header('Location: attendance.php');
    } else {
        $_SESSION['status'] = "Your data is NOT updated";
        $_SESSION['status_code'] = "error";
        header('Location: attendance.php');
    }
}

How do I convert my current HTML and CSS page (with the changes the user did) to a PDF file that can

                No comments   

 Those features which Tim mentioned all use the fact that the user's browser has already rendered the HTML/CSS/JavaScript?/etc page into a displayable (and therefore printable) format.

So if you want to do that on the server side, you're going to need something which simulates that process. I have no doubt that you can find that thing on the web, and I recommend that you do look for it there. Trying to write it yourself would not be a simple process.

HTTP 405 (Method not allowed) error

                No comments   

 I am developing a web-app in

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Visual Studio code
, which takes input from an user into a form and registers the values into a
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MYSQL
database. The code is as follows:


HTML code (basically fetching the values from a form and sending them to the php script):

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function submit(n,i,p,e,img){
 
        alert(n+""+i+""+p+""+""+e+""+img);
        $.ajax({
            type : "POST",  //type of method
            url  : "/database_registration.php",  
            data : { name_1 : n, email_1 : e, image : img, org_number_1: i, ph_number_1: p },
            success: function(){  
                                  
                                    alert("success!!");
                    }
        });
     
         
    }
     
    const dForm = document.getElementById('details');          
    dForm.addEventListener('submit', function(e) {
        e.preventDefault()
        submit(nme,id,phone,email,img);
    });
     
    var arr=document.cookie.split(';')
    for(var i=0; i<arr.length; i++){
     
        var c=arr[i].split('=');
        if (c[0].trim()=='name'){
            var nme=c[1];
            document.getElementsByName("name_1")[0].innerHTML=nme;
        }
        else if(c[0].trim()=='ID No'){
            var id=c[1];
            document.getElementsByName("org_number_1")[0].innerHTML=id;
        }
        else if(c[0].trim()=='Mobile No'){
            var phone=c[1];
            document.getElementsByName("ph_number_1")[0].innerHTML=phone;
        }
        else if(c[0].trim()=='Email'){
            var email=c[1];
            document.getElementsByName("email_1")[0].innerHTML=email;
        }
    }
     
    const image = localStorage.getItem("Image");
    var img=image;
    document.getElementsByName("image")[0].src=image;


php script (Storing the values into a MYSQL database):

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<?php
    header("Access-Control-Allow-Origin: *");
    header("Access-Control-Allow-Methods: GET, POST, OPTIONS");
      
    $servername = "localhost";
       
    $username = "root";
       
    $password = "";
     
    $date = date("Y-m-d");
     
    echo 'Post variables:<br />';
    print_r($_POST);
     
    if (isset($_POST["name_1"]))
        $name=$_POST['name_1'];
    if (isset($_POST["org_number_1"]))
        $org_number=$_POST['org_number_1'];
    if (isset($_POST["ph_number_1"]))
        $ph_number=$_POST['ph_number_1'];
    if (isset($_POST["email_1"]))
        $email=$_POST['email_1'];
    if (isset($_POST["image"]))
        $image=$_POST['image'];
     
    $conn = new mysqli($servername,  
                $username, $password, "Employee_information");
       
    if ($conn->connect_error) {
        die("Connection failure: "
            . $conn->connect_error);
    }  
       
    $sql="CREATE TABLE IF NOT EXISTS Employees(Sl_no int AUTO_INCREMENT PRIMARY KEY, Full_name varchar(30) NOT NULL,
          ID_no INT(2) NOT NULL UNIQUE, Contact INT(10) NOT NULL UNIQUE, Email varchar(30) NOT NULL UNIQUE, registration_date DATE,
          ID_preview blob(10M))";
    $conn -> query($sql);
     
    $stmt = $conn->prepare("INSERT INTO Employees (Full_name, ID_no, Contact, Email,
                                        registration_date, ID_preview)
                                        VALUES (?, ?, ?, ?, ?, ?)");
    $stmt->bind_param("siissb", $name, $org_number, $ph_number, $email, $date, $image);
    $stmt->execute();
     
    if($stmt->execute())
        echo "records inserted";
    else
        echo $stmt->error;
       
    $stmt->close();
    $conn->close();
    ?>


Error:

Failed to load resource: the server responded with a status of 405 (Method not allowed)

Posting dropdown value to database

                No comments   

 Hello.

First of all, i want to apologize for my question, since the code im about to post is way outdated.

I am hosting this script on a server which is running a very old version of php.

The website is used by me and 2 other friends, and we are the only ones able to connect to it, due to .htaccess only showing the page to recognized ip adresses.. So there is no need to protect against sql injection or anything.

Now that thats out of the way, here is the problem i am facing:

i have a php script, which is showing a dropdown menu, with values gathered from a mysql table called chat_clothes.

I then have a submit button, that is supposed to post whatever you have chosen in the dropdown menu, to another table called chat_brugere

But when i click the submit button, it posts "Resource id #7", instead of the selected value.

Here is my code:

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<?php
@session_start();
header('Content-Type: text/html; charset=ISO-8859-1');
include('includes/config.php');
?>
        <link rel="stylesheet" type="text/css" href="css/chat.css" />
<div id="sidebar_header">Garderobe</div>
<div id="sidebar_content">
    <p style="display: inline;">Skid i havet.</p><br /><br />
    <select name="sko">
<?php
 
    if(isset($_SESSION['logget_ind']) && $_SESSION['logget_ind'] == true) {
        $getSko = mysql_query("SELECT `navn` FROM `chat_clothes` WHERE `ejer` = '".$_SESSION['brugernavn']."' AND `type` = 'sko'");
 
         
        while ($showSko = mysql_fetch_array($getSko)) {
            echo '<option id="sko" name="sko" style="width: 300px;">'.$showSko['navn'].'</option><br />'
            ;
            }
    }
?>
 
</div>
 
            </select>
<?php
    if (isset($_POST['sko'])) {
         
 
                        mysql_query("UPDATE chat_brugere SET shoes='".$getSko."' WHERE id='".$_SESSION['id']."'");
 
                        echo 'sko er opdateret!';
                } else {
                    echo '';
                }
             
            echo '
            <form action="nygad.php" method="POST">
 
                <div>
                    <table>
                     
                        <tr>
                            <td><center><input type="submit" name="sko" value="Opdater!" /></center></td>
                        </tr>
                    </table>
                </div>
            </form>
            ';
        ?>

How my Dog learned Polymorphism

                No comments   

How my Dog learned Polymorphism

So, Clover, let's review from our last lesson...

What do you get when you do this:

Dog d = new Dog();

You get a new Dog object right? An instance of class Dog, referenced by a variable named "d". [tail wags]

Good Girl! Here's a treat...

So let's go beyond that. First, I'm going to show you a class inheritance tree for the example we're going to work on:

This means:

Dog extends Animal
Animal is a superclass of Dog
Dog is a subclass of Animal
Dog inherits from Animal
Dog overrides the play() method
Dog adds one new method, bark()

Ruff!

Yes, very good.
So what happens now if I say:

Dog d = new Dog();
d.play();

[cocks head sideways]

Which play() method is called -- the one in Dog, or the one inherited from Animal?

Dog overrides the play() method, so you get the play() method in Dog.

Of course. That's what overriding means. The subclass object has "extended" the superclass by adding more specific functionality to the play() method.

OK, now what if I say...

Animal d = new Dog();

Is that code even legal? Will it compile?

Yes! Because Dog "is a" Animal. (or so you keep reminding me). Dog is a subclass of Animal, so I know that it's legal to have a reference type which is a superclass of the actual object type. Here, let me draw it [puts marker in mouth]

 

 

Wow! I had no idea you could draw. And yes, that's correct. The reference type and the object type don't always match, but the rule is:

If the reference type is a class, the object it refers to MUST be either that same type or a subclass of that type.

If the reference type is an INTERFACE, the object it refers to MUST be an object from a class which implements the interface (either directly or through inheritance).

I understand how it works, but doesn't it "trick" a programmer into thinking that he (or she) has an Animal object when really a Dog object is hiding out there on the heap?

But what's the danger in that? A Dog can do ANYTHING an Animal can do (and more). So there's no harm. A programmer can safely call methods on the Animal reference, as though the object were really an Animal. The object is guaranteed to be able to respond to those method calls.

But let's get to the Big Question:

Animal d = new Dog();
d.play();

Which play() is really called? The one in Animal, or the one in Dog?

Here's a hint: Java uses "late-binding" for instance methods.

Oh, well, that explains it...

Late-binding means Java doesn't "bind" (think: choose) a method call to an actual method at compile time. The choice of method happens later... at run-time.

Compile time = early, run-time = late. I get it.

Yes, exactly.

So Java waits to see what the ACTUAL object is... rather than using the reference type! Cool. [wags tail again]

You're really a smart dog, Clover. Despite what those sheep say.
And you're right.
Java does the right thing at run-time.
So if a Dog object is at the other end of an Animal reference, you still get the Dog version of the method. Always. It's not like this in C++, where a method has to marked "virtual" if you want to get this "polymorphic" behavior where the method is looked-up at run-time, LATE.

Based on the actual object's class, not the reference type.

But I still have another question... WHY would you want to do this? If you wanted the Dog to play (is now OK?) why not just use a Dog reference? Why use the Animal reference?

Referring to an object in many different ways (reference type is different from actual object class) is the point of polymorphism, which means "many forms". I can treat a Dog object like a Dog, or I can treat it like an Animal, or I can even treat it like a Pet, when I have the Dog class implement the Pet interface.

...and the reason for this would be...

Many reasons. Here's a good one...
You have a program that uses many different animal subclasses, and tells all the animals to play().

You could put all of the different animal subclass objects into an Animal [] array rather than keeping them in separate arrays for each subclass type.

Then you can loop through the Animal [] array and tell each element to play().

And the RIGHT play() method will be called for the REAL object at each slot in the array... am I right?

Yes! So the Compiler is...

.What, no treat? [doing that cute, sad, dog look]

Hang on and let me finish. So the Compiler is happy, since it knows that Animal has a play() method, it knows that each animal in the array can be safely treated like an Animal.

And if any element in the array happens to be a subclass of Animal, and it overrides the play() method, then a different play() method will be called for that element.

Late. The choice of the method is made "late".

At run-time.

So why not just use a generic collection like Vector? Can't you just put any object in there -- they don't even have to be from the same inheritance tree.

You've missed the point. A Vector would be less efficient, for one thing, and you'd have to cast the objects back to something more specific before you could call methods (other than, say, toString()).

What a pain. And that's not the main problem.

What if another programmer comes along after the guy who wrote the Animal program is gone? What if you don't even have his source code, but you need to add a new animal subclass like Cow? If all the different Animal subclasses had to be figured out, and cast, etc. then you could not add new Cow animals into the program without changing the original code.

But if the Animal program is simply expecting an array of Animals, then all I have to do is make my new Cow class a subclass of Animal, then it can be safely included in an Animal [] array and passed to a method in the Animal program.

So that's what you meant about extensibility with object-oriented programming...

Good girl! Yes -- that's part of what makes OOP so cool. OK, here's your treat. Now go write some code for me and I promise to keep the sheep away from your Duke chew toy.

[In Clover's next lesson, we'll be tackling AWT event-handling]

Vue.js Custom Directives

                No comments   

 

Vue.js Custom Directives

Vue.js directives are used in Vue.js applications to make them reusable and straightforward. Directives are just like instructions that can be used in Vue.js applications to do things in a specific way. We have already used simple conditional directives such as v-if, v-show, v-else, v-for, v-bind, v-model, v-on, etc. in our https://coderfunda.blogspot.com/ page.

Here, we will learn how to create custom and global directives and use them just like we did in Vue. js components https://coderfunda.blogspot.com/ because Vue.js allows us to create our own custom directives.

Syntax:

Example Explanation

In the above example, you can see that we have created a custom directive named "changestyle" as following:

  1. Vue.directive("changestyle",{  
  2.    bind(e1,binding, vnode) {  
  3.       console.log(e1);  
  4.       e1.style.color = "red";  
  5.       e1.style.fontSize = "20px";  
  6.    }  
  7. });  

Now, the custom directive "changestyle" is assigned to a div as follows:

  1. <div v-changestyle>Vue.js Custom Directive Example</div>  

How to pass a value to the custom directive?

We can pass values to the custom directive by binding values to them. Binding is like arguments passed to the custom directive.

Syntax:

  1. v-changestyle = "{color:'the_color_name'}".   

Let's take an example to demonstrate how to pass a value to the custom directive.

Index.html:

  1. <html>  
  2.    <head>  
  3.       <title>Vue.js Custom Directive</title>  
  4.       <link rel="stylesheet" href="index.css">  
  5.         <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>  
  6.     </head>  
  7.     <body>  
  8.       <div id = "directive">  
  9.           <div v-changestyle = "{color:'green'}">Passing value to custom directive example</div>  
  10.       </div>  
  11.       <script type = "text/javascript">  
  12.          Vue.directive("changestyle",{  
  13.             bind(e1,binding, vnode) {  
  14.                console.log(e1);  
  15.                console.log(binding.value.color);  
  16.                console.log(vnode);  
  17.                e1.style.color=binding.value.color;  
  18.                e1.style.fontSize = "20px";  
  19.             }  
  20.          });  
  21.       </script>  
  22.       <script src="index.js"></script>  
  23.    </body>  
  24. </html>  

Index.js:

  1. var vm = new Vue({  
  2.             el: '#directive',  
  3.             data: {  
  4.             },  
  5.             methods : {  
  6.             },  
  7.          })  

After the execution of the program, you will see the following output:

Output:

Vue.js Custom Directives

You can see that the value is passed in the directive and the color of the text is changed to green. The value is passed by using the following code:

  1. <div v-changestyle = "{color:'green'}">Passing value to custom directive example</div>   

It is accessed by using the following code:

  1. Vue.directive("changestyle",{  
  2.    bind(e1,binding, vnode) {  
  3.       console.log(e1);  
  4.       console.log(binding.value.color);  
  5.       console.log(vnode);  
  6.       e1.style.color=binding.value.color;  
  7.       e1.style.fontSize = "20px";  
  8.    }  
  9. });  

Using Filters with Custom Directives

Vue.js supports filters that can be used in text formatting. The filters are generally used along with v-bind and interpolations ({{}}). We require using a pipe symbol at the end of JavaScript expression for filters.

Let's see an example to demonstrate the use of filters in the custom directive.

Index.html file:

  1. <html>  
  2.    <head>  
  3.       <title>Vue.js Custom Directive</title>  
  4.       <link rel="stylesheet" href="index.css">  
  5.         <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>  
  6.     </head>  
  7.     <body>  
  8.       <div id = "directive">  
  9.                   <input  v-model = "name" placeholder = "Enter Your Name" /><br/>  
  10.          <span style = "font-size:20px;"><b>Letter count is : {{name | countletters}}</b></span>  
  11.       </div>  
  12.       </script>  
  13.       <script src="index.js"></script>  
  14.    </body>  
  15. </html>  

Index.js file:

  1. var vm = new Vue({  
  2.             el: '#directive',  
  3.            data: {  
  4.                name : ""  
  5.             },  
  6.             filters : {  
  7.                countletters : function(value) {  
  8.                   return value.length;  
  9.                }  
  10.             }  
  11.          })  

After the execution of the program, you will see the following output:

Output:

Vue.js Custom Directives

When you type any text in the above box, you can get the letter count as follows:

Vue.js Custom Directives

Example Explanation

In the above example, you can see that we have created a simple filter named "countletters". The countletters filter counts the numbers of characters entered in the textbox. We have to use the filter property and define the used filter as follows:

  1. filters : {  
  2.    countletters : function(value) {  
  3.       return value.length;  
  4.    }  
  5. }  

Here, we have defined the method countletters and then returned the length of the entered string.

Now, we have used the pipe operator and the name of the filter "countletters" to display the filter's result in output:

  1. <span style = "font-size:20px;"><b>Letter count is : {{name | countletters}}</b></span> 

 

 
 
  1. Vue.directive('name_of_the_directive', {  
  2.    bind(e1, binding, vnode) {  
  3.    }  
  4. })   

To create a custom directive, we have to use Vue.directive and the name of the directive, as shown in the above syntax. Let us see an example to demonstrate how to create a custom directive and how to use it.

Index.html file:

  1. <html>  
  2.    <head>  
  3.       <title>Vue.js Custom Directive</title>  
  4.       <link rel="stylesheet" href="index.css">  
  5.         <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>  
  6.     </head>  
  7.     <body>  
  8.       <div id = "directive">  
  9.           <div v-changestyle>Vue.js Custom Directive Example</div>  
  10.       </div>  
  11.        <script type = "text/javascript">  
  12.          Vue.directive("changestyle",{  
  13.             bind(e1,binding, vnode) {  
  14.                console.log(e1);  
  15.                e1.style.color = "red";  
  16.                e1.style.fontSize = "20px";  
  17.             }  
  18.          });  
  19.          var vm = new Vue({  
  20.             el: '#directive',  
  21.             data: {  
  22.             },  
  23.             methods : {  
  24.             },  
  25.          });  
  26.       </script>  
  27.       <script src="index.js"></script>  
  28.    </body>  
  29. </html>  

Index.js file:

  1. var vm = new Vue({  
  2.             el: '#directive',  
  3.             data: {  
  4.             },  
  5.             methods : {  
  6.             },  
  7.          })  

Let's use a simple CSS file to make the output more attractive.

Index.css file:

  1. html, body {  
  2.     margin: 5px;  
  3.     padding: 0;  
  4. }  

After the execution of the program, you will see the following output:

Source : javatpoint

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