Searching, $_POST variable - php

Question

I have this code block in html for inputting the search.
<?php echo form_open('bookstore/_searchbook'); ?>
<table>
<tr>
<td>
<label for="searchid">Search:</label>
</td>
<td>
<input type="text" size="15" name="searchid" />
</td>
</tr>
<tr>
<td>
<label for="searchtype">Type:</label>
</td>
<td>
<select>
<option value="book_id">Id</option>
<option value="book_author">Author</option>
<option value="book_name">Title</option>
</select>
</td>
</tr>
<tr>
<input type="submit" value="Search" />
</tr>
</table>
<?php echo form_close(); ?>
And i have this on my controller,
public function booksearch()
{
if($_POST['submit'])
{
$col= $this->input->post('searchtype', TRUE);
$val= $this->input->post('searchval', TRUE);
$data['book'] = $this->books_model->showbook($col,$val);
$this->load->view('showbooks',$data);
}
}
and this would be my model
public function showbook($col, $searchid)
{
$this->db->select()->from('books')->where(array($col=>$searchid));
$query=$this->db->get();
return $query->first_row('array');
}
Further info on my view,
I have this to print the results of my search.
<table cellpadding='5'>
<th>Book ID</th>
<th>Title</th>
<th>Author</th>
<th>Released Year</th>
<th>ISBN</th>
<?php
if(isset($books)) : foreach($books as $book) :
?>
<tr>
<td><?php echo $book['book_id'] ?></td>
<td><?php echo $book['book_name'] ?></td>
<td><?php echo $book['book_author'] ?></td>
<td><?php echo $book['book_year'] ?></td>
<td><?php echo $book['book_isbn'] ?></td>
</tr>
<?php
endforeach;
?>
<?php
else :
?>
<h5>No records</h5>
<?php
endif;
?>
</table>
It returns nothing so all i see is no records. Someone direct me to the thing i did wrong.

Answer 1

Your form's action (view) is _searchbook while your controller function is booksearch
Your submit input needs a name attribute
in the controller function you have $data['book'] while in your view (in the foreach loop) you reference that variable as $books
Model: you need to select at least something; e.g. $this->db->select('*')->from('books')->where(array($col=>$searchid)); instead of $this->db->select()
Model: I think you need return $query->result_array(); instead of $query->first_row('array')

Answer 2

Because your submit button has not got any name attribute. Instead of if($_POST['submit']) write $this->input->post(null)

Answer 3

Try adding global $_POST; to the top of your function. In php all variables used(declaired) in a function will be private unless you tell it otherwise by adding it to the global statement in the function.
public function booksearch()
{
global $_POST;
if($_POST['submit'])
{
$col= $this->input->post('searchtype', TRUE);
$val= $this->input->post('searchval', TRUE);
return $data['book'] = $this->books_model->showbook($col,$val);
}
}