How to Delete a Record with a Custom Plugin using wpdb

Posted on 18th June 2023

Introduction

In this tutorial, we will learn how to delete a record with a custom plugin using wpdb.

Requirements

To follow this tutorial, you will need:

• A WordPress site
• A code editor

Step 1: Create the Plugin

First, we need to create a plugin. We can do this by creating a new directory in the WordPress plugin directory. For this tutorial, we will name our plugin “delete-record-with-wpdb”.

Step 2: Create the Plugin File

Next, we need to create the plugin file. We will name this file “delete-record-with-wpdb.php”.

Step 3: Register the Plugin

Now we need to register the plugin. We can do this by adding the following code to the top of our plugin file:


<?php
/*
Plugin Name: Delete Record With wpdb
Plugin URI: https://example.com/
Description: This plugin delete a record with wpdb.
Version: 1.0
Author: John Doe
Author URI: https://example.com/
*/
?>


Step 4: Add the Plugin Code

Now we need to add the code for our plugin. We will add the following code to our plugin file:


<?php
// include the wpdb class
if ( ! class_exists( 'wpdb' ) ) {
require_once( ABSPATH . 'wp-admin/includes/class-wpdb.php' );
}

global $wpdb;

// set the table name
$table_name = $wpdb->prefix . "mytable";

// set the ID of the record to delete
$id = 1;

// delete the record
$wpdb->delete( $table_name, array( 'ID' => $id ) );
?>


Step 5: Activate the Plugin

Now we need to activate the plugin. We can do this by going to the WordPress admin area and clicking on the “Plugins” link. Then, find the plugin in the list and click on the “Activate” link.

Step 6: Verify the Plugin is Working

To verify that the plugin is working, we can check the WordPress database. We can do this by going to the “Tools” -> “phpMyAdmin” link in the WordPress admin area. Then, select the WordPress database and click on the “SQL” tab. In the “Run SQL query/queries on database” box, we can enter the following SQL query:


SELECT * FROM wp_mytable;


If the plugin is working, we should see the record with an ID of “1” in the database table.

Conclusion

In this tutorial, we learned how to delete a record with a custom plugin using wpdb.

wpdb provides a few helper functions that you can use to delete data from the database. In this tutorial, we will learn how to use two of these functions: wpdb::delete() and wpdb::query().

We will also learn how to write our own custom SQL query to delete data from the database.

How to Delete Data using wpdb::delete()

The wpdb::delete() function takes two arguments: the table name and an array of conditions.

The conditions array is used to specify which records should be deleted. The array keys are the column names and the array values are the column values.

For example, the following code will delete all posts with the post_status of “trash”:

$wpdb->delete( $wpdb->posts, array( ‘post_status’ => ‘trash’ ) );

If you want to delete multiple records, you can specify multiple conditions using the WP_Query class:

$query = new WP_Query( array( ‘post_status’ => ‘trash’, ‘posts_per_page’ => -1 ) ); while ( $query->have_posts() ) { $query->the_post(); $wpdb->delete( $wpdb->posts, array( ‘ID’ => get_the_ID() ) ); }

How to Delete Data using wpdb::query()

The wpdb::query() function can be used to run any SQL query. This function takes two arguments: the SQL query and an optional array of variables.

The SQL query can be a string or a prepared statement. A prepared statement is a SQL query that contains placeholders for variables.

The variables are passed as the second argument to the wpdb::query() function. They will be replaced by their actual values when the query is executed.

For example, the following code will delete all posts with the post_status of “trash”:

$sql = “DELETE FROM $wpdb->posts WHERE post_status = ‘trash'”; $wpdb->query( $sql );

If you want to delete multiple records, you can use a prepared statement:

$sql = “DELETE FROM $wpdb->posts WHERE post_status = %s”; $wpdb->query( $sql, ‘trash’ );

How to Delete Data using a Custom SQL Query

You can also write your own SQL query to delete data from the database.

For example, the following code will delete all posts with the post_status of “trash”:

$sql = “DELETE FROM $wpdb->posts WHERE post_status = ‘trash'”; $wpdb->query( $sql );

You can also use a prepared statement:

$sql = “DELETE FROM $wpdb->posts WHERE post_status = %s”; $wpdb->query( $sql, ‘trash’ );

Conclusion

In this tutorial, we learned how to delete data from the database using the wpdb::delete() and wpdb::query() functions.

We also learned how to write our own custom SQL query to delete data from the database.

If you want to delete a record associated with a WordPress post, you need to use the wpdb class. This class gives you the ability to interact directly with the WordPress database.

In order to delete a record, you need to first get the ID of the record you want to delete. You can do this by running a query on the wpdb object.

Once you have the ID, you can then delete the record by running the following query:

DELETE FROM wp_posts WHERE ID = ‘$id’

This will delete the record with the ID that you specified. You can also delete multiple records by specifying multiple IDs in the query.

You can also use the wpdb class to delete records from any other table in the WordPress database. Just replace the wp_posts table in the query with the name of the table you want to delete from.

Assuming you have a custom plugin that uses the WordPress database access layer (wpdb), you can delete a record by using the $wpdb->delete method. This method takes two parameters: the table name and an array of conditions (in column => value pairs) to match.

For example, to delete a record from the wp_posts table where the ID is 5:

$wpdb->delete( ‘wp_posts’, array( ‘ID’ => 5 ) );