Chetan Upare

WordPress does not provide a native way to model real relationships between content items such as posts, users, and terms. 
Most solutions rely on post meta or taxonomies, which become difficult to query, scale, and maintain over time.
If you’ve outgrown ACF relationship fields or post meta arrays, Native Content Relationships introduces a structured relationship layer for WordPress that allows you to define meaningful, queryable, and scalable relationships between content — without relying on hacks or editor-specific solutions.
This plugin is designed to be core-friendly, developer-focused, and future-proof, built specifically for developers who have hit performance walls.
<h3>What This Plugin Solves</h3>
• Many-to-many relationships between content 
• Clean querying without meta or taxonomy abuse 
• Long-term maintainability and portability 
• Cleanly handles headless and REST WordPress setups
<h3>Key Features</h3>
• Relationships between posts, users, and terms 
• One-way or bidirectional relationships 
• Indexed database table for fast queries 
• Clean PHP API for managing relationships 
• WP_Query integration 
• REST API support with inline relations 
• Multilingual-ready (WPML / Polylang) 
• WooCommerce optional integration 
• Editor- and theme-agnostic
<h3>Supported Relationship Types</h3>
• Post ↔ Post 
• Post ↔ User 
• Post ↔ Term 
• User ↔ Post 
• Term ↔ Post
<h3>Common Use Cases</h3>
Posts 
• Products → Accessories 
• Courses → Lessons 
• Articles → Related content
Users 
• Favorite posts 
• Bookmarked content 
• Multiple authors or contributors
Terms 
• Featured categories 
• Curated collections 
• Semantic grouping beyond default taxonomies
<h3>Admin Interface</h3>
• Relationship management in post editor 
• User profile relationship management 
• Term editor relationship support 
• AJAX-powered search for posts, users, and terms 
• Modern UI matching WordPress admin style
<h3>Stability & Backward Compatibility</h3>
Schema stable from 1.x onward. Backward compatibility guaranteed.
We lock the core before expanding. Ecosystem and agency confidence depend on it.
<ul>
<li>Database schema stability — The relationship table and <code>NCR_SCHEMA_VERSION</code> are stable in the 1.x line. Any future schema change will be additive (new columns/indexes) or run through a documented migration; no breaking table or column renames without a major version.</li>
<li>Backward compatibility promise — Public PHP APIs (functions, hooks, WP_Query arguments), shortcodes, and REST endpoints will not be removed or changed in breaking ways within the 1.x branch. Deprecations will be announced and supported for at least one minor version.</li>
<li>Versioning policy — 1.x = stable core. Minor/patch releases may add features and fix bugs; they will not break existing integrations. A major version (2.x) would be the only place for intentional breaking changes, with a clear migration path.</li>
<li>Namespacing discipline — One internal prefix: <code>ncr_</code> (functions, hooks, options), <code>NCR_</code> (classes, constants), <code>ncr-</code> (CSS/IDs/handles). No new alternate prefixes; documented and consistent so extensions and ecosystem plugins can rely on a stable surface.</li>
</ul>
<h3>Architected for Performance & Scale</h3>
Native Content Relationships is built for high-volume enterprise and headless WordPress sites. Forget the performance bottleneck of post-meta.
<ul>
<li>Index Optimization: Built on composite covering indexes (<code>type_lookup</code>) and a smart query planner optimized for performance.</li>
<li>Micro-Optimized Validations: SQL-native validations ensure sub-2ms P95 latency even at 1M+ rows.</li>
<li>Object Cache Integration: Full compatibility with object cache through group isolation, targeted relationship cache invalidation, and bulk priming strategies.</li>
<li>Performance Diagnostics: Includes a powerful CLI diagnostic utility to check and fix integrity without UI bloat.</li>
</ul>
Benchmarks confirm stable performance with 1,000,000+ relationship rows under InnoDB. 
<a href="https://github.com/chetanupare/WP-Native-Content-Relationships/blob/main/docs/PERFORMANCE.md" rel="nofollow ugc">View Full Performance Report</a>
<h3>ACF Migration (Escape Meta Technical Debt)</h3>
If you store relationships in Advanced Custom Fields relationship fields or standard Post Meta, you can safely migrate to Native Content Relationships to unlock immediate performance and querying benefits.
A built-in script allows you to selectively migrate ACF related data into the new performant table, allowing you to gradually refactor out technical debt. 
Check out the dedicated one-time migration guide here: <a href="https://github.com/chetanupare/WP-Native-Content-Relationships/blob/main/docs/migration/from-acf.md" rel="nofollow ugc">docs/migration/from-acf.md</a>
<h3>Advanced Developer APIs</h3>
Built to be a complete content relationship modeling engine:
<ul>
<li>Relationship Type Registration API: Programmatic type registration for custom relationships, with schema validation and strict directional logic.</li>
<li>Relationship Constraints: Declare relationship constraints like 1:1, 1:N, or M:N and strictly enforce maximum capacities and duplicates. </li>
<li>Advanced Query Parameters: Inject the <code>content_relation</code> argument directly into your <code>WP_Query</code> with parameters specifically designed for advanced use cases: include multiple relationship types, apply exclusionary rules, combine <code>OR</code>/<code>AND</code> relations, or filter by minimum/maximum thresholds. </li>
<li>Bulk Operations API: Optimized batch operations to bulk attach, bulk detach, and WP-CLI data import designed specifically for use cases when scaling up and executing large workloads.</li>
<li>Lightweight Metadata Add context to relationships natively using relationship metadata (allow order rankings, contexts, descriptions, tracking data, etc.) via a dedicated relationship metadata registry and table.</li>
<li>Graph Utility Layer An ultra-minimal set of APIs and WP-CLI commands that generate graph diagnostics—useful for acquiring relationship counts, calculating the most connected posts, isolating orphaned items, and running background integrity checks.</li>
</ul>
<h3>Headless REST Readiness</h3>
For decoupled and highly dynamic solutions, Native Content Relationships includes powerful headless optimizations:
Append <code>?naticore_relations=1</code> or <code>?_embed=relations</code> into your standard core endpoint fetches (e.g., <code>wp/v2/posts</code>) to embed related data inside your response arrays instantly, minimizing round trips.
<h3>Integrations</h3>
• WooCommerce (product relationships) 
• WPML / Polylang (relationship mirroring) 
• Elementor (dynamic content support) 
• Gutenberg (related content block) 
• Advanced Custom Fields (one-time migration tool)
<h3>Page Builder Integration</h3>
Elementor: 
* Compatible with: Elementor 2.0+ 
* Features: Comprehensive Dynamic Tags suite for relationships 
* Auto-detected: Yes (no configuration needed) 
* Tested up to: Elementor 3.20
Elementor Dynamic Tags: 
* Related Posts: Display related posts with customizable output formats 
* Related Users: Display users with relationships (favorites, bookmarks, etc.) 
* Related Terms: Display taxonomy terms with relationships 
* Flexible Output: IDs, titles, links, avatars, count-only options 
* Direction Support: Both outgoing and incoming relationships 
* Native Controls: Relationship type selector with validation
Gutenberg: 
* Compatible with: WordPress 5.0+ (Core) 
* Features: “Related Content” block with relationship filtering 
* Always available: Yes (core WordPress feature) 
* Tested up to: WordPress 6.5
<h4>Shortcodes</h4>
Use these in posts, pages, or widgets. They use the current post ID when not specified.
Related posts (default: type=related_to, limit=5): 
[naticore_related_posts type=”related_to” limit=”5″ order=”date” layout=”list” title=”Related Content” class=”my-class”]
Related users (default: type=authored_by): 
[naticore_related_users type=”authored_by” limit=”10″ order=”name” layout=”list” title=”Authors”]
Related terms (default: type=categorized_as): 
[naticore_related_terms type=”categorized_as” limit=”5″ order=”name” layout=”grid” title=”Categories”]
Attributes (all shortcodes): 
* type – Relationship type slug (e.g. related_to, parent_of, authored_by, categorized_as) 
* limit – Number of items (1–50), default 5 
* order – Sort: date, title (posts) or name (users/terms) 
* post_id – Post ID; omit to use current post 
* layout – list or grid 
* title – Heading text above the list (optional) 
* class – Extra CSS class(es) for the wrapper 
* show_thumbnail – 1 to show post thumbnail (posts shortcode only), default 0 
* excerpt_length – Number of words for excerpt (0 = hide), default 0
<h4>Widget</h4>
Related Content (NCR) is available under Appearance → Widgets. Add it to any sidebar or widget area.
<ul>
<li>Title – Optional widget title (leave blank to use the shortcode’s default “Related Content” heading)</li>
<li>Relationship type – e.g. Related To, Parent Of, Depends On</li>
<li>Number of items – 1–50</li>
<li>Order by – Date or Title</li>
<li>Post ID (optional) – Leave 0 to use the current post; set a post ID to show relations for a specific post</li>
</ul>
Output matches the shortcode (same markup and styles when the shortcode CSS is enqueued).
<h3>Developer Guide (Advanced)</h3>
This section is intended for developers who want programmatic control.
<h4>Core API</h4>
Add a relationship: 
 wp_add_relation( $from_id, $to_id, $type );
Get related items: 
 wp_get_related( $id, $type );
Check relationship: 
 wp_is_related( $from_id, $to_id, $type );
Remove relationship: 
 wp_remove_relation( $from_id, $to_id, $type );
<h4>WP_Query Integration</h4>
new WP_Query( array( 
‘post_type’ => ‘post’, 
‘content_relation’ => array( 
‘post_id’ => 123, 
‘type’ => ‘related_to’, 
), 
) );
<h4>REST API</h4>
Endpoints available under: 
 /wp-json/naticore/v1/
• Create relationships 
• Fetch related content 
• Delete relationships
Embed relations in core REST responses (headless): 
Add <code>?naticore_relations=1</code> to any core resource request to include a <code>naticore_relations</code> array in the response. Works with: 
• <code>GET /wp-json/wp/v2/posts/<id>?naticore_relations=1</code> 
• <code>GET /wp-json/wp/v2/users/<id>?naticore_relations=1</code> 
• <code>GET /wp-json/wp/v2/categories/<id>?naticore_relations=1</code> (and other taxonomies) 
Each relation item includes <code>to_id</code>, <code>to_type</code>, <code>type</code>, and optional <code>title</code>/<code>display_name</code>/<code>name</code>. Opt-in only so default requests stay fast.
<h4>Hooks & Filters</h4>
Actions: 
• <code>naticore_relation_added</code> 
• <code>naticore_relation_removed</code> 
• <code>naticore_after_duplicate_post</code> – fired after copying relations from one post to another (args: from_post_id, to_post_id, result array)
Filters: 
• <code>naticore_relation_is_allowed</code> 
• <code>naticore_get_related_args</code>
Duplicate post: Use helper <code>naticore_copy_relations( $from_post_id, $to_post_id, $relation_types = null )</code> to copy relationships when duplicating a post. Returns array with keys <code>copied</code>, <code>skipped</code>, <code>errors</code>. Out-of-the-box integration: Yoast Duplicate Post, Post Duplicator (metaphorcreations), Copy & Delete Posts (Inisev).
<h4>Elementor Integration</h4>
This plugin provides comprehensive Elementor Dynamic Tags for displaying relationships in Elementor-powered designs.
Available Dynamic Tags:
<ul>
<li>
Related Posts (ncr-related-posts)
<ul>
<li>Display posts related to the current post</li>
<li>Supports all post-to-post relationship types</li>
<li>Output formats: IDs, titles, links, count</li>
<li>Direction control: outgoing/incoming</li>
</ul>
</li>
<li>
Related Users (ncr-related-users)
<ul>
<li>Display users with relationships to posts</li>
<li>Supports user relationship types (favorites, bookmarks, etc.)</li>
<li>Output formats: IDs, names, emails, avatars, profile links</li>
<li>Direction control: posts-to-users/users-to-posts</li>
</ul>
</li>
<li>
Related Terms (ncr-related-terms)
<ul>
<li>Display taxonomy terms with relationships</li>
<li>Supports term relationship types (categories, tags, etc.)</li>
<li>Output formats: IDs, names, slugs, archive links</li>
<li>Direction control: posts-to-terms/terms-to-posts</li>
</ul>
</li>
</ul>
Usage Examples:
Display related post IDs: 
 <code>[ncr-related-posts relationship_type="related_to" output_format="ids" limit="5"]</code>
Display user avatars: 
 <code>[ncr-related-users relationship_type="favorite_posts" output_format="avatar_images" avatar_size="48"]</code>
Display term links: 
 <code>[ncr-related-terms relationship_type="categorized_as" output_format="term_links" limit="10"]</code>
Get count of related items: 
 <code>[ncr-related-posts relationship_type="related_to" output_format="count"]</code>
Advanced Features: 
– Context-aware: Automatically detects current post, user, or term context 
– Fallback content: Display custom text when no relationships found 
– Pagination support: Limit results for performance 
– Ordering options: Sort by date, title, or random 
– Multi-language: Works with WPML/Polylang translations
Integration Benefits: 
– Native Elementor experience: Tags appear in Elementor’s Dynamic Tags panel 
– No templates forced: Users control output format and styling 
– Performance optimized: Uses cached relationship data 
– Optional dependency: Only loads when Elementor is active
<h4>WP-CLI</h4>
• List relationships 
• Add / remove relationships 
• Integrity checks
<h3>Contributing</h3>
Contributions are welcome. 
GitHub: https://github.com/chetanupare/WP-Native-Content-Relationships
<h3>License</h3>
GPLv2 or later

Native Content Relationships

Add first-class relationships between posts, users, and terms using a fast, structured, and scalable architecture.

Tran Ngoc Tuan Anh

Meta Box

truongwp

Doan Ngoc Anh

hsimah

MB Relationships helps you create relationships between posts, pages, custom post type, terms and users. 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.
<blockquote>
Meta Box Lite 
 We recommend using <a href="https://metabox.io/lite/" rel="nofollow ugc">Meta Box Lite</a>, a feature-rich free UI version of Meta Box that provides UI and all free features for managing custom fields and dynamic content on WordPress, including post types, taxonomies, custom fields, and relationships.
</blockquote>
It supports reciprocal and bi-directional relationships.
<h3>Why Do You Need Posts To Posts Relationships In WordPress?</h3>
Post relationships is a missing part in WordPress. The only “built-in” way that mimic the post relationship in WordPress is the <code>post_parent</code> 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:
<h4>Creating Related Posts In WordPress</h4>
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.
<h4>Example: Events And Bands</h4>
Suppose you have two custom post types, event and band, where:
<ul>
<li>In each event there may be multiple bands, and</li>
<li>Each band can participate in many events.</li>
</ul>
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.
<h3>Bi-directional relationships</h3>
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.
<h3>An Alternative For The Posts 2 Posts Plugin (P2P Plugin)</h3>
MB Relationships is very much inspired by the popular plugin <a href="https://wordpress.org/plugins/posts-to-posts/" rel="ugc">Posts 2 Posts</a> which is not maintained anymore. We have taken the idea and made some improvements. The codebase and data structure is very similar.
<h3>Plugin features</h3>
<ul>
<li>Simple APIs: the plugin provides simple APIs for registering relationships and retrieving connected items. It integrates with existing WordPress APIs such as <code>WP_Query</code>,<code>get_terms</code> and <code>get_users</code>. See <a href="https://docs.metabox.io/extensions/mb-relationships/" rel="nofollow ugc">documentation</a> for more information.</li>
<li>Uses custom relationship table to store relationships. That helps optimize the database storage and query performance.</li>
<li>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 <a href="https://metabox.io/plugins/mb-term-meta/" rel="nofollow ugc">MB Term Meta</a> and <a href="https://metabox.io/plugins/mb-user-meta/" rel="nofollow ugc">MB User Meta</a>.</li>
<li>Supports creating reciprocal relationships (posts-posts, users-users, …).</li>
<li>Supports creating bi-directional relationships and easily query them.</li>
<li>Display connected items easily with shortcode.</li>
<li>Extremely lightweight and fast.</li>
</ul>
<h3>Plugin Links</h3>
<ul>
<li><a href="https://metabox.io/plugins/mb-relationships/" rel="nofollow ugc">Project Page</a></li>
<li><a href="https://github.com/wpmetabox/mb-relationships/" rel="nofollow ugc">Github Repo</a></li>
</ul>
This plugin is a free extension of <a href="https://metabox.io" rel="nofollow ugc">Meta Box</a> plugin, which is a powerful, professional solution to create custom fields and custom meta boxes for WordPress websites. Using MB Relationships in combination with <a href="https://metabox.io/plugins/" rel="nofollow ugc">other extensions</a> will help you manage any content types in WordPress easily and make your website more professional.
<h3>You might also like</h3>
If you like this plugin, you might also like our other WordPress products:
<ul>
<li><a href="https://wpslimseo.com" rel="nofollow ugc">Slim SEO</a> – A fast, lightweight and full-featured SEO plugin for WordPress with minimal configuration.</li>
<li><a href="https://wpfalcon.pro" rel="nofollow ugc">Falcon</a> – A lightweight companion for making WordPress faster, cleaner, and more secure.</li>
<li><a href="https://gretathemes.com" rel="nofollow ugc">GretaThemes</a> – Free and premium WordPress themes that clean, simple and just work.</li>
<li><a href="https://wpautolistings.com" rel="nofollow ugc">Auto Listings</a> – A car sale and dealership plugin for WordPress.</li>
</ul>

MB Relationships

👏🏽👏🏽👏🏽👏🏽👏🏽👏🏽👏🏽

This makes many-to-many so easy

A lightweight solution for creating relationships between posts, terms and users in WordPress.

Native Content Relationships vs MB Relationships