遇到PHP错误严重性:通知消息:试图获得非对象的属性文件名:blog/index.php行号:23

index.php文件行号。

         echo ucfirst($author->username);

我的控制器文件夹中的blog_model.php文件如下:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Blog_model extends CI_Model {
 function get_posts()
  {
    $this->db->order_by('entry_date','desc'); // get all entry, sort by latest to oldest
    $query = $this->db->get('entry');
    return $query->result();
  }
function add_new_entry($author,$name,$body,$categories)
{
    $data = array(
        'author_id'     => $author,
        'entry_name'    => $name,
        'entry_body'    => $body,
    );
    $this->db->insert('entry',$data);
    $object_id = (int) mysql_insert_id(); // get latest post id
  foreach($categories as $category)
    {
        $relationship = array(
            'object_id'     => $object_id, // object id is post id
            'category_id'   => $category,
        );
        $this->db->insert('entry_relationships',$relationship);
    }
}
function add_new_comment($post_id, $commentor, $email, $comment, $user_id)
{
    $total_count = 0;
    $data = array(
        'entry_id'      => $post_id,
        'comment_name'  => $commentor,
        'comment_email' => $email,
        'comment_body'  => $comment,
        'user_id'       => $user_id,
    );
    $this->db->insert('comment',$data);
    $query = $this->get_post($post_id);
    foreach($query as $post)
    {
        $total_count = $post->comment_count + 1;
    }
    $count = array(
        'comment_count' => $total_count,
    );
    $this->db->where('entry_id',$post_id);
    $query = $this->db->update('entry',$count); // update comment count
}
function get_post($id)
{
    $this->db->where('entry_id',$id);
    $query = $this->db->get('entry');
    if($query->num_rows()!==0)
    {
        return $query->result();
    }
    else
        return FALSE;
}
function get_post_comment($post_id)
{
    $this->db->where('entry_id',$post_id);
    $query = $this->db->get('comment');
    return $query->result();
}
function total_comments($id)
{
    $this->db->like('entry_id', $id);
    $this->db->from('comment');
    return $this->db->count_all_results();
}
function add_new_category($name,$slug)
{
    $i = 0;
    $slug_taken = FALSE;
    while( $slug_taken ==  FALSE ) // to avoid duplicate slug
    {
        $category = $this->get_category(NULL,$slug);
        if( $category == FALSE )
        {
            $slug_taken = TRUE;
            $data = array(
                'category_name' => $name,
                'slug'          => $slug,
            );
            $this->db->insert('entry_category',$data);
        }
        $i = $i + 1;
        $slug = $slug.'-'.$i;
    }
}
function get_category($id = FALSE, $slug)
{
    if( $id != FALSE)
        $this->db->where('category_id',$id);
    elseif( $slug )
        $this->db->where('slug',$slug);
    $query = $this->db->get('entry_category');
    if( $query->num_rows() !== 0 )
    {
        return $query->result();
    }
    else
        return FALSE; // return false if no category in database
}
function get_categories()
{
    $query = $this->db->get('entry_category'); 
    return $query->result();
}
function get_related_categories($post_id)
  {
    $category = array();
    $this->db->where('object_id',$post_id);
    $query = $this->db->get('entry_relationships'); // get category id related to the post
    foreach($query->result() as $row)
    {
        $this->db->where('category_id',$row->category_id);
        $query = $this->db->get('entry_category'); // get category details
        $category = array_merge($category,$query->result());
    }
    return $category;
}
function get_category_post($slug)
{
    $list_post = array();
    $this->db->where('slug',$slug);
    $query = $this->db->get('entry_category'); // get category id
    if( $query->num_rows() == 0 )
        show_404();
    foreach($query->result() as $category)
    {
        $this->db->where('category_id',$category->category_id);
        $query = $this->db->get('entry_relationships'); // get posts id which related the category
        $posts = $query->result();
    }
    if( isset($posts) && $posts )
    {
        foreach($posts as $post)
        {
            $list_post = array_merge($list_post,$this->get_post($post->object_id)); // get posts and merge them into array
        }       
    }
    return $list_post; // return an array of post object
}

}

/*结束文件blog_model.php //位置:./application/models/blog_model.php */