README

MB Relationships helps you create many-to-many relationships between posts, pages or any custom post type. The plugin is lightweight and optimized for database and query performance.

The plugin allows you to create connections from posts to posts, posts to pages and so on. Then you can perform corresponding queries to retrieve posts that are connected to or from given posts.

It supports reciprocal and bi-directional relationships.

Why Do You Need Posts To Posts Relationships In WordPress?

Post relationships is a missing part in WordPress. The only "built-in" way that mimic the post relationship in WordPress is the post_parent for pages where you can create many child pages of a page (a one-to-many relationship). Unfortunately, that's available for pages and hierarchical post types only. Besides, it's not many-to-many relationship.

Below are some examples of posts to posts relationships that might help you see the benefit of this feature:

Creating Related Posts In WordPress

The simplest example is to manually create related posts in your WordPress website. When you edit a post, you can select posts that have similar or related content and display them in the frontend for further reading.

You can also query backward: displaying posts that link to the being read post as a reference to provide more information to your readers. With this, you don't need a WordPress related posts plugin anymore.

Example: Events And Bands

Suppose you have two custom post types, event and band, where:

In each event there may be multiple bands, and
Each band can participate in many events.

If people want to buy tickets, they could search for events in their location and see what bands are playing on a given date, or they could search for bands they like and see what date they are playing near their location.

In this example, we have created many-to-many relationships between events and bands.

Bi-directional relationships

MB Relationships allows you to create bi-directional connections. You will be able to query back and forth without any problem.

The data is stored in the database as a pair of (from_id, to_id), thus making it independent from either side.

Besides, for each side, there's a meta box that shows what are connected from/to. So you don't have to worry about the direction of the connection anymore.

An Alternative For The Posts 2 Posts Plugin (P2P Plugin)

MB Relationships is very much inspired by the popular plugin Posts 2 Posts which is not maintained anymore. We have taken the idea and made some improvements. The codebase and data structure is very similar.

Plugin features

Simple APIs: the plugin provides simple APIs for registering relationships and retrieving connected items. It integrates with existing WordPress APIs such as WP_Query, get_terms and get_users. See documentation for more information.
REST API: the plugin provides a REST API to manage relationships programatically. See documentation for more information.
Uses custom relationship table to store relationships. That helps optimize the database storage and query performance.
You can create relationships between any kind of content in WordPress: posts to posts, posts to users, etc. For posts to terms and posts to users, it's required the MB Term Meta and MB User Meta.
Supports creating reciprocal relationships (posts-posts, users-users, ...).
Supports creating bi-directional relationships and easily query them.
Display connected items easily with shortcode.
Extremely lightweight and fast.

Plugin Links

This plugin is a free extension of Meta Box plugin, which is a powerful, professional solution to create custom fields and custom meta boxes for WordPress websites. Using MB Relationships in combination with other extensions will help you manage any content types in WordPress easily and make your website more professional.

If you like this plugin, you might also like our other WordPress products:

Meta Box - The most powerful WordPress plugin for creating custom post types and custom fields.
Slim SEO - A fast, lightweight and full-featured SEO plugin for WordPress with minimal configuration.
Slim SEO Schema - An advanced, powerful and flexible plugin to add schemas to WordPress.
Slim SEO Link Manager - Build internal link easier in WordPress with real-time reports.
GretaThemes - Free and premium WordPress themes that clean, simple and just work.
Auto Listings - A car sale and dealership plugin for WordPress

Installation

You need to install Meta Box plugin first

Go to Plugins | Add New and search for Meta Box
Click Install Now button to install the plugin
After installing, click Activate Plugin to activate the plugin

Install MB Relationships extension

Go to Plugins | Add New and search for MB Relationships
Click Install Now button to install the plugin
After installing, click Activate Plugin to activate the plugin

wpmetabox / mb-relationships

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