Integration with Wordpress authentication

You can point the wp_user and wp_usermeta tables to others in the same DB using the following constants in wp-config.php :

define( 'CUSTOM_USER_TABLE', $table_prefix.'my_users' );
define( 'CUSTOM_USER_META_TABLE', $table_prefix.'my_usermeta' );

The point is that these other tables must have the same structure as WP :

Related: Make website login work on WordPress too and SSO / authentication integration with external 'directory service' .

I refer to my experience in a solution that I worked on. In my specific case the authentication system was independent of Wordpress and the management system. In Wordpress a plugin built for the effect authenticates the user in the authentication system and in the management system the same thing happened.

After successful authentication some of the user fields were updated in Wordpress as it is necessary for some plugins that you can install that will require some of that user information not to mention Wordpress itself.

The separate authentication system has many advantages because it separates the services and puts specialization in each of the services. It can also centralize credentials for many other benefits.

Using WebServices and managing TOKENS for example, it was possible manage users' actions so that they only authenticate once, even though they use the various services available.