uninstall.php

<?php
//if uninstall not called from WordPress exit
if ( !defined( 'WP_UNINSTALL_PLUGIN' ) )
    exit ();

global $wpdb;

$kbe_tbl_prefix = $wpdb->prefix;
	
//=========> Delete Plugin Settings From options Table
delete_option('kbe_bgcolor');
delete_option('kbe_plugin_slug');
delete_option('kbe_article_qty');
delete_option('kbe_sidebar_home');
delete_option('kbe_sidebar_inner');
delete_option('kbe_search_setting');
delete_option('kbe_comments_setting');
delete_option('kbe_taxonomy_children');
delete_option('kbe_breadcrumbs_setting');
delete_option('widget_kbe_tags_widgets');
delete_option('widget_kbe_search_widget');
delete_option('widget_kbe_article_widget');
delete_option('widget_kbe_category_widget');
	
//=========> Delete `terms_order` Column From trms Table
$wpdb->query("ALTER TABLE ".$kbe_tbl_prefix."terms DROP COLUMN `terms_order`");
	
//=========> Get Knowledgebase page and Delete all relivent Data
$kbe_get_page = $wpdb->get_results("Select * From ".$wpdb->prefix."posts
                                    Where post_content like '%[kbe_knowledgebase]%'
                                    and post_type = 'page'");
				
foreach($kbe_get_page as $get_page){
    $kbe_page_ID = $get_page->ID;

    //Delete all Knowledgebase page Relivent data from `postmeta` Table
    $wpdb->query("Delete From ".$wpdb->prefix."postmeta Where post_id = $kbe_page_ID");

    //Delete all Knowledgebase page Child data from `posts` Table
    $wpdb->query("Delete From ".$wpdb->prefix."posts Where post_parent = $kbe_page_ID");

    //Delete Knowledgebase page from `posts` Table
    $wpdb->query("Delete From ".$wpdb->prefix."posts Where ID = $kbe_page_ID");
}
	
//=========> Get all Images of `kbe_knowledgebase` post type and Delete all Images Data
$kbe_get_post_images = $wpdb->get_results("Select * From ".$wpdb->prefix."posts Where post_type = 'kbe_knowledgebase'");

$kbe_upload_dir = wp_upload_dir();

foreach($kbe_get_post_images as $get_post_images){
    $kbe_posts_img_ID = $get_post_images->ID;

    $kbe_post_imgs_qry = $wpdb->get_results("Select * From ".$wpdb->prefix."posts
                                             Where post_parent = $kbe_posts_img_ID
                                             And post_type = 'attachment'
                                             And post_mime_type = 'image/jpeg'");
    foreach($kbe_post_imgs_qry as $get_post_img){
        $kbe_img_ID = $get_post_img->ID;

        // Extract path from images
        $kbe_img_path = get_post_meta($kbe_img_ID, "_wp_attached_file", true);
        $kbe_main_img_name = substr( $kbe_img_path, strrpos( $kbe_img_path, '/' )+1 );
        $kbe_sub_path = substr($kbe_img_path, 0, strrpos( $kbe_img_path, '/'));

        $kbe_img_meta = get_post_meta($kbe_img_ID, "_wp_attachment_metadata", true);

        $kbe_thumbnail = $kbe_img_meta['sizes']['thumbnail']['file']; 
        $kbe_medium = $kbe_img_meta['sizes']['medium']['file']; 
        $kbe_post_thumbnail = $kbe_img_meta['sizes']['post-thumbnail']['file'];

        $kbe_upload_path = $kbe_upload_dir["basedir"];

        unlink($kbe_upload_path."/".$kbe_sub_path."/".$kbe_main_img_name);
        unlink($kbe_upload_path."/".$kbe_sub_path."/".$kbe_thumbnail);
        unlink($kbe_upload_path."/".$kbe_sub_path."/".$kbe_medium);
        unlink($kbe_upload_path."/".$kbe_sub_path."/".$kbe_post_thumbnail);

        //Delete all Knowledgebase Posts from `posts` Table
        $wpdb->query("Delete From ".$wpdb->prefix."postmeta Where post_id = $kbe_img_ID");
    }
}
	
//=========> Get all Posts of `kbe_knowledgebase` post type and Delete all relivent Data
$kbe_get_posts = $wpdb->get_results("Select * From ".$wpdb->prefix."posts Where post_type = 'kbe_knowledgebase'");

foreach($kbe_get_posts as $get_posts){
    $kbe_posts_ID = $get_posts->ID;

    //Delete all Comments of `kbe_knowledgebase` posts from `comments` Table
    $wpdb->query("Delete From ".$wpdb->prefix."comments Where comment_post_ID = $kbe_posts_ID");

    //Delete all Meta Data of `kbe_knowledgebase` posts from `postmeta` Table
    $wpdb->query("Delete From ".$wpdb->prefix."postmeta Where post_id = $kbe_posts_ID");

    //Delete all `kbe_knowledgebase` posts Realtion Data from `term_relationships` Table
    $wpdb->query("Delete From ".$wpdb->prefix."term_relationships Where object_id = $kbe_posts_ID");

    //Delete all `kbe_knowledgebase` Child data from `posts` Table
    $wpdb->query("Delete From ".$wpdb->prefix."posts Where post_parent = $kbe_posts_ID");

    //Delete all Knowledgebase Posts from `posts` Table
    $wpdb->query("Delete From ".$wpdb->prefix."posts Where ID = $kbe_posts_ID");
}
	
//=========> Delete All Categories and Tags of Knowledgebase
$kbe_get_terms = $wpdb->get_results("Select kbe_term.*, kbe_tax.*
                                     From ".$wpdb->prefix."terms As kbe_term
                                     Inner join ".$wpdb->prefix."term_taxonomy As kbe_tax
                                     On kbe_term.term_id = kbe_tax.term_id
                                     Where kbe_tax.taxonomy = 'kbe_taxonomy'
                                     Or kbe_tax.taxonomy = 'kbe_tags'");

foreach($kbe_get_terms as $get_term){
    $kbe_term_ID = $get_term->term_id;

    $wpdb->query("Delete From ".$wpdb->prefix."terms Where term_id = $kbe_term_ID");
}
	
//=========> Delete All Taxonomies and Tags of Knowledgebase
$wpdb->query("Delete From ".$wpdb->prefix."term_taxonomy Where taxonomy = 'kbe_taxonomy'");

$wpdb->query("Delete From ".$wpdb->prefix."term_taxonomy Where taxonomy = 'kbe_tags'");