Introduction to custom post type relationships

In general, we use relational databases in developing applications, where each model will be matched to a separate database table. Each model will be related to one or more than one module, but in WordPress, we have all of the custom post types stored in the posts table. Therefore, it's not possible to create relationships between different post types with the existing functionality.

Note

WordPress developers around the world have been conducting discussions to get the post relationship capability built into the core. Even though the response from the WordPress core development seems positive, we still don't have it on the core version as of 3.6. You can have a look at an interesting discussion at: http://make.wordpress.org/core/2013/07/28/potential-roadmap-for-taxonomy-meta-and-post-relationships/.

Since this is one of the most important aspects of web application development, we have no choice other than looking for a custom solution built by...