Problem:

The customer needed to migrate a custom many-to-many (m2m) database setup, with separate tables for articles, writers, and their relationship, into WordPress using Toolset. They sought guidance for this process, particularly for handling m2m relationships, as available tutorials primarily covered one-to-many (o2m) relationships.

Solution:

The migration to a WordPress-compatible many-to-many structure with Toolset involves several steps:

1- Create Custom Post Types: Using Toolset, set up custom post types for "Articles" and "Writers" to match the existing data structure.

2- Establish the Many-to-Many Relationship: Toolset supports defining many-to-many relationships directly between custom post types. An intermediary relationship can link "Articles" and "Writers," reflecting the original database’s structure.

3- Prepare Data for Import: Export the current data tables (articles, writers, and articleswriters) as CSV files to facilitate data import.

4- Use a CSV Import Plugin: With a plugin like WP All Import, map the data into the respective custom post types in WordPress, and ensure the relationships between articles and writers are accurately represented.

5- Display and Manage Content: Toolset enables the creation of front-end templates for displaying the articles and writers, showcasing their relationships.

Relevant Documentation:

https://toolset.com/documentation/programmer-reference/how-to-import-a-database-into-wordpress/