Pie Chart using PHP and JS

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How to create a Pie Chart using PHP and JavaScript

Pie charts are the most fun chart to draw and to broadcast whole-to-part relationship. Here are steps showing how to create a pie chart using PHP and JavaScript with Pluscharts, a JavaScript charting library to build charts.

Step 1: To create the MySQL table

For this, consider a table of data, consisting of seven data entries. The columns are labeled id, month and sales. This table can be created using the following code.

CREATE TABLE shop (
id INT NOT NULL,
month VARCHAR(30) NOT NULL,
sales INT NOT NULL,
 PRIMARY KEY (id),  
 UNIQUE (month)
);

INSERT INTO shop
   (id, month, sales)
VALUES
   (1, “Jan”, 50),
   (2, “Feb”, 10),
   (3, “Mar”, 20),
   (4, “Apr”, 20),
   (5, “May”, 30),
   (6, “Jun”, 10),
   (7, “Jul”, 20);

Step 2:  To set up the connection between the database and the main file

Once the data is stored in the database, you can start with creating your project folder and the main file. But before you begin with the main code, don’t forget to create a subfolder (optional), to hold the secondary files that need to be included in the main code.

Now, let us move to create a new file, that will contain a PHP code to fetch the data from the database.

<?php

$dbservername = “localhost”;

$dbusername = “”;

$dbpassword = “”;

$dbname = “test”;

$conn = mysqli_connect($dbservername, $dbusername, $dbpassword, $dbname);

if (!$conn) {

die(“Connection failed: “. mysqli_connect_error());

}

?>

Include the file, in the main file and in order to check the connection establishment, run the code in the browser, preferably Chrome. Store both sets of data, months and sales in two arrays.

<?php  

include_once ‘dbh.php’;

$sql= “SELECT*FROM shop”;

$result= mysqli_query($conn, $sql);

$shops= array();

if (mysqli_num_rows($result) >0)

{

   while ($row= mysqli_fetch_assoc($result)) {

 

   $shops[]= $row;

}

}

$a= array();

foreach ($shops as $shop) {

$a[]= $shop[‘sales’];

}

$b= array();

foreach ($shops as $shop) {

$b[]= $shop[‘month’];

}

?>

Step 3: Writing the Pie Chart example code

Create an element, where you want to render your chart, using the following code.

For example, here we create an element with id, ‘pie-chart-example’.

<div id=”pie-chart-example”></div>

Now, since the pluscharts library is built upon d3, we load d3 first and then pluscharts, using the following scripts.

   <script src=”https://d3js.org/d3.v5.min.js”></script>

               <script src=”path-to/src/pluscharts.js”></script>

After that we assign the data from PHP to JS variables, using the following code.

<script type=”text/javascript”>

   var sales= <?php echo json_encode($a ); ?>;

  var months= <?php echo json_encode($b ); ?>;

After this, we can move to write a JavaScript code to create a column chart.

pluscharts.draw({

   drawOn : “#pie-chart-example”,

   type: “pie”,

   dataset : {

       data: sales,

       backgroundColor: [“#6182ce”, “#d18a96”, “#81c0a7”],

       borderColor: “#633e77”,

       borderWidth: 2,

       label: months

   },

   options: {

       text: {

           display: true,

           color: “#fdfdfd”

       },

       legends: {

           display: true,

           width: 20,

           height: 20

       },

       size: {

           width: ‘400’, //give ‘container’ if you want width and height of initiated container

           height: ‘400’

       }

   }

})

 </script>

Let’s break this simple code further down to understand it better.

pluscharts.draw

({   })

This function is used to initiate the chart. Under this draw function, we pass the details of the chart including the data and options as an argument to the draw() function.

   drawOn : ‘#pie-chart-example’,

The drawOn element is used to indicate the element where the chart is to be generated.

   type: “pie”,

The type of chart to be drawn is specified in the type element.

dataset: {

       data: sales,

       backgroundColor: [“#6182ce”, “#d18a96”, “#81c0a7”],

       borderColor: “#633e77”,

       borderWidth: 2,

       label: months

   },

The dataset is used to insert data values, background color, border color, border width, label and legend labels. Note that here, instead of specifying the data values in data and labels, we have given the name of the array where the data is stored, which is “sales” and “labels” respectively.

options: {

       text: {

           display: true,

           color: “#fdfdfd”

       },

       legends: {

           display: true,

           width: 20,

           height: 20

       },

       size: {

           width: ‘400’, //give ‘container’ if you want width and height of initiated container

           height: ‘400’

       }

   }

})

Options are where the whole customization of the chart is done. Here, we specify the bar padding and the colors of the bars representing the data. The color can be specified directly or a specific color code can be written and the text display and size can also be customized. There are also options to set the visibility and dimensions of legends. The total size of the chart can be set here. Instead of a number, ‘container’ can be given in as a value, when there is a need to set the chart to the same width and height as its initiated container.

Sowmya

Sowmya

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