Plot from mysql database

Question

I'm trying to plot just a simple x-y line graph with the data obtained from a MySQL database. The code is the following one:

<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/flot/0.8.3/jquery.flot.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.js"></script>
</head>
<body>
    <h3><b>Database</b></h3>
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "prueba2";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
     die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, username, password, email, x, y FROM user";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    echo "<table>
             <tr>
                 <th>ID</th>
                 <th>Username</th>
                 <th>Password</th>
                 <th>Email</th>
                 <th>X</th>
                 <th>Y</th>
               </tr>";
     // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "
             <tr>
                 <td>" . $row["id"]. "</td>
                 <td>" . $row["username"]. "</td>
                 <td>" . $row["password"]. "</td>
                 <td>" . $row["email"]. "</td>
                 <td>" . $row["x"]. "</td>
                 <td>" . $row["y"]. "</td>
            </tr>";
    }
    echo "</table>";
    $dataset1 = array();
    while ($row = $result->fetch_assoc()) {
        $dataset1[] = array(intval($row["x"]),intval($row["y"]));
    }
} else {
     echo "0 results";
}
$conn->close();
?>
<br>
<h3>Test plot</h2>
<div id="placeholder"></div>
<script type="text/javascript">
        var dataset1 = <?php echo json_encode($dataset1); ?>;
        $(function () {
             $.plot($("#placeholder"), [ dataset1 ]);
        });
</script>
</body>
</html>

The result I get is the table perfectly set but an empty Flot Chart plot. That's to say the data is loaded correctly but I'm not able to plot it or to store it in variables or maybe the flot charts syntaxis is not well/well placed. Any suggestions? Thanks!

Renzo · Accepted Answer · 2015-06-27 12:03:04Z

1

The problem is that the assignment to the array is done after the first while, that produces the rows for the html table, when the result has been already fetched by the server. So the second loop exit immediately without assigning anything.

You should do the assignment inside the first loop, after the echo statement.

answered Jun 27, 2015 at 12:03

Renzo

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1 Comment

jquery_stack Over a year ago

Yes! Thank you very much. I've just placed the array assignment inside the first while loop and now it loads the data perfectly :)

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