How to handle empty array in codeigniter? - php

Question

So these are my codes.
model
function read() {
$sql= "SELECT * from table WHERE name = 'rabin'";
$query = $this->db->query($sql);
$res = $query->result_array();
return $res;
}
controller
function show() {
$this->load->model("db");
$array['data'] = $this->db->read();
$this->load->view("page", $array);
}
view
foreach($data as $val) {
"<p>" . echo $val['name']; . "</p>"
"<p>" . echo $val['address']; . "</p>"
}
Here, when there are no records in the database satisfying the WHERE clause in the query, the model returns null and I get error saying $data expects parameter 1 to be array, null given. There are several methods to deal with this situation. But, what would be the best possible way to handle this situation ?

Answer 1

The problem is the foreach needs data provided by the database, but you didn't give them anyone.
So I will do this instead:
Model
function read() {
$this->db->where('name', 'rabin');
$res = $this->db->get('table');
return ($res->num_rows() > 0) ? $query->result_array() : false;
}
Controller
function show() {
// $this->(model_name)->(function);
$result = $this->db_model->read();
if ( $result ) {
// if there has data returns, load view
$array['data'] = $result;
$this->load->view('page', $array);
}
else {
// otherwise, show errors.
// you can handle by yourself
echo "no result!";
}
}
Use the Query Builder always to prevent from SQL Injection.
The Model returns the result_array, or false, so that you can handle the result.
Use $res->row_array() instead if your query result returns only one row. (like the certain one member).
You should rename your model from db to (example)db_model or other. The db will conflict with the system method.
The way to load function from model is $this->model_name->function_name for example, it should be $this->db_model->read().
You should load the model (if it is db_model) like $this->load->model('db_model') in public function __construct() { }.

Answer 2

In your model try out this
function read() {
$this->db->select()->from('table')->where('name', 'rabin');
$sql_stmt = $this->db->get();
return $sql_stmt->result();
}
and then to check you are getting the result - in your controller,
function show() {
$this->load->model("db");
$array= array( 'data' => $this->db->read());
$this->load->view("page", $array);
}
To view the result in your view file do print_r($data);
And then let me know what you get / result

Answer 3

In your view put if than else block with foreach loop in it. Smething like:
<?php if ($data != FALSE): ?>
<?php
foreach($data as $val)
{
"<p>" . echo $val['name']; . "</p>"
"<p>" . echo $val['address']; . "</p>"
}
?>
<?php else: ?>
<?php echo "There is no demanded data."; ?>
<?php endif; ?>

Answer 4

This is much like Benyi's answer with a little twist.
Probably you will eventually want the model to be able to look for names other than 'rabin'. So this shows how to accomplish that by passing a value to the model. Also, this model method always returns something useful to the controller.
function read($name)
{
$noRecords[] = array('name' => "No Results!", 'address' => "");
if(empty($name))
{
return $noRecords;
}
//Such a simple query does not require Query Builder which adds a
//lot of extra processing to get to the same place as this query statement
$sql = "SELECT * from table WHERE name = ?";
//This is a "bound" query that will escape the input to guard against injection attacks
$query = $this->db->query($sql, array($name));
$res = $query->result_array();
if($res->num_rows() > 0)
{
return $query->result_array();
}
else
{
// send the controller an array containing a little something to explain what happened
return $noRecords;
}
//the above if/else could also be expressed with this ternary
// return $res->num_rows() > 0 ? $query->result_array() : $noRecords;
}
The controller is now very light-weight.
function show()
{
$name = 'rabin'; //some data for the model
$array['data'] = $this->db_model->read($name);
$this->load->view('page', $array);
}
Your view is also greatly simplified
<?php foreach($data as $val): ?>
<p><?php echo $val['name']; ?>"</p>"
<p><?php echo $val['address']; ?>"</p>"
<?php endforeach; ?>