pagination using php pdo mysql - php

Question

I have attempted to set up pagination for a simple database table which selected everything from the database table and displays it in a table for the user however i have been having issues with this. I followed a tutorial which shows how to set up the pagination but i keep encountering a SQLSTATE[42000]: Syntax error or access violation: 1327 Undeclared variable: $startrow error and I'm not sure why.
this is the code:
<?php
include "db_conx.php";
//check if the starting row variable was passed in the URL or not
if (!isset($_GET['startrow']) or !is_numeric($_GET['startrow'])) {
//we give the value of the starting row to 0 because nothing was found in URL
$startrow = 0;
//otherwise we take the value from the URL
} else {
$startrow = (int)$_GET['startrow'];
}
try {
$db_conx = new PDO("mysql:host=$mysql_hostname;dbname=$mysql_dbname", $mysql_username, $mysql_password);
$db_conx->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$stmt = $db_conx->prepare('SELECT * FROM role_type LIMIT $startrow, 3');
$stmt->execute();
$roles = $stmt->fetchAll(PDO::FETCH_ASSOC);
}
catch(Exception $e)
{
die ("Could not connect to the database $mysql_dbname :" . $e->getMessage());
}
?>
<h4><center>Manage Role Types</center></h4>
<div class="container">
<div class = "container-fluid">
<div id = "table_container" style="width:auto; margin-top:50px;" class="mainbox col-md-6">
<div class="row clearfix">
<div class="col-md-12">
<table class="table table-bordered table-hover" id="tab_logic">
<thead>
<tr >
<th class="text-center">
Role Type Code
</th>
<th class="text-center">
Role Title
</th>
</tr>
</thead>
<tbody>
<!-- populating the table with information from mysql database -->
<?php foreach ($roles as $row) {
echo "<tr><td>";
echo $row['role_type_code'];
echo "</td><td>";
echo $row['role_title'];
echo "</td><td>";
echo '<p data-placement="top"
data-toggle="tooltip"
style="margin-left:5px"
title="Edit">';
echo '<button class="btn btn-primary btn-xs"
data-title="Edit"
data-toggle="modal"
data-id="';
echo $row['role_type_code'];
echo '" data-role="';
echo $row['role_title'];
echo '" data-target="#editModal">';
echo '<span class="glyphicon glyphicon-edit" />';
echo '</button></p>';
echo "</td>";
echo "</td><td>";
echo '<p data-placement="top"
data-toggle="tooltip"
style="margin-left:5px"
title="Delete">';
echo '<button class="btn btn-danger btn-xs"
data-title="Delete"
data-toggle="modal"
data-id="';
echo $row['role_type_code'];
echo '" data-role="';
echo $row['role_title'];
echo '" data-target="#deleteModal">';
echo '<span class="glyphicon glyphicon-trash" />';
echo '</button></p>';
echo "</tr>"; }
?>
</tbody>
</table>
<?PHP
//now this is the link..
echo 'Next';
$prev = $startrow - 10;
//only print a "Previous" link if a "Next" was clicked
if ($prev >= 0)
echo 'Previous';
?>
</div>
</div>
no idea why. I've tried using a value in place of the variable but it doesn't work. Any body know how i can overcome this please.
thank you

Answer 1

You can NOT embed php variable in SINGLE quoted strings http://php.net/language.types.string
So your query is wrong
$stmt = $db_conx->prepare('SELECT * FROM role_type LIMIT $startrow, 3');
It needs to be
$stmt = $db_conx->prepare("SELECT * FROM role_type LIMIT $startrow, 3");