How to Implement Pagination using wpdb in WordPress Plugin

Posted on 20th June 2023

Introduction
In this article, we will be discussing how to implement pagination using the wpdb class in WordPress. The wpdb class is the core class used for interacting with a WordPress database. In order to use pagination with wpdb, we will need to make use of the $wpdb->get_results() method. This method accepts an SQL query as its first argument and an integer as its second argument. The integer specifies the number of rows to return from the database.

We will be making use of a custom WordPress plugin that we have created for this purpose. The plugin will be used to display a list of posts from the WordPress database. We will make use of the $wpdb->get_results() method to query the database and return the results. We will then use the WordPress paginate_links() function to display links to the next and previous pages of results.

The code for the custom plugin is as follows:

strategy ) ) {
$instance->strategy = new WP_DB_Pagination_Strategy_Default( $instance );
}

return $instance;
}

WP_DB_Pagination();

In the code above, we have defined a custom WordPress plugin that we will use to demonstrate how to implement pagination using the wpdb class. The plugin includes a number of files, which we will discuss in more detail below.

The first file that we include is the main plugin file, which contains the plugin header information. This information is used by WordPress to display the plugin name, description, version, and author information in the WordPress admin area.

The second file that we include is the interface for the pagination strategy. This interface defines the methods that must be implemented by a pagination strategy. A pagination strategy is used to determine how the pagination links are displayed on the page.

The third file that we include is the default pagination strategy. This strategy is used if no other pagination strategy is specified. It simply displays the pagination links in a list format.

The fourth file that we include is the WP_DB_Query class. This class is used to query the WordPress database. It contains a number of methods for performing various database operations.

The fifth and final file that we include is the WP_DB_Pagination_Strategy class. This class is used to implement the pagination strategy interface. It contains a number of methods for displaying the pagination links on the page.

The WP_DB_Pagination class is the main class for the plugin. It contains a number of methods for setting up and managing the pagination. The first method that we need to look at is the __construct() method. This method initializes the plugin and sets up the default pagination strategy.

The next method that we need to look at is the query() method. This method accepts an SQL query as its first argument and an integer as its second argument. The integer specifies the number of rows to return from the database.

The query() method is used to query the WordPress database. It uses the $wpdb->get_results() method to execute the SQL query and return the results. The results are stored in an array and returned by the method.

The next method that we need to look at is the get_pagination_links() method. This method accepts an array of arguments as its only argument. The arguments are used to configure the pagination links.

The get_pagination_links() method uses the WordPress paginate_links() function to generate the pagination links. The links are returned as an HTML string.

The final method that we need to look at is the get_pagination_link() method. This method accepts an integer as its only argument. The integer specifies the page number to return the pagination link for.

The get_pagination_link() method returns the pagination link for the specified page number. The link is returned as an HTML string.

The WP_DB_Pagination class also contains a number of helper methods. These methods are used to generate the SQL queries and HTML strings used by the plugin.

The WP_DB_Pagination_Strategy class is used to implement the pagination strategy interface. It contains a number of methods for displaying the pagination links on the page.

The first method that we need to look at is the get_pagination_links() method. This method accepts an array of arguments as its only argument. The arguments are used to configure the pagination links.

The get_pagination_links() method uses the WordPress paginate_links() function to generate the pagination links. The links are returned as an HTML string.

The next method that we need to look at is the get_pagination_link() method. This method accepts an integer as its only argument. The integer specifies the page number to return the pagination link for.

The get_pagination_link() method returns the pagination link for the specified page number. The link is returned as an HTML string.

The WP_DB_Pagination_Strategy class also contains a number of helper methods. These methods are used to generate the SQL queries and HTML strings used by the plugin.

The WP_DB_Query class is used to query the WordPress database. It contains a number of methods for performing various database operations.

The first method that we need to look at is the query() method. This method accepts an SQL query as its first argument and an integer as its second argument. The integer specifies the number of rows to return from the database.

The query() method is used to query the WordPress database. It uses the $wpdb->get_results() method to execute the SQL query and return the results. The results are stored in an array and returned by the method.

The next method that we need to look at is the get_posts() method. This method accepts an array of arguments as its only argument. The arguments are used to configure the SQL query.

The get_posts() method uses the WordPress get_posts() function to execute the SQL query and return the results. The results are stored in an array and returned by the method.

The final method that we need to look at is the get_post() method. This method accepts an integer as its only argument. The integer specifies the post ID to return.

The get_post() method returns the post with the specified ID. The post is returned as an object.

The WP_DB_Query class also contains a number of helper methods. These methods are used to generate the SQL queries and HTML strings used by the plugin.

In order to use the plugin, we need to include the following code in our WordPress theme:

<?php

// Include the plugin class
require_once( 'path/to/plugin/class-wp-db-pagination.php' );

// Instantiate the plugin class
$plugin = new WP_