Provides a utility class for the Participants Database Multi-Relational plugin that can be used in a shortcode template

pdbmrdb_record.php

<?php

/**
 * Plugin Name: PDb Multi-Relational Utility Class
 * Description: Provides a utility class for showing a record's relations
 * Version: 0.1
 */

class pdbmrdb_record {
  
  /**
   * @var int the record id
   */
  private $record_id = 0;
  
  /**
   * @var array of all the record's relations
   * 
   * this is indexed by the typename, each element will be an array as $record_id => $title
   */
  private $relations = [];
  
  /**
   * builds the object
   * 
   * @param int $record_id
   */
  public function __construct( $record_id )
  {
    $this->assign_record_id( $record_id );
    
    if ( $record_id )
    {
      $this->build_relations();
    }
  }
  
  /**
   * provides a list of the record's relations for the given type
   * 
   * return empty array if no relations of the type are set
   * 
   * @param string $typename
   * @return array as $record_id => $title
   */
  public function get_relations( $typename )
  {
    return isset( $this->relations[ $typename ] ) ? $this->relations[ $typename ] : [];
  }
  
  /**
   * assigns the record id
   * 
   * @param int $record_id
   */
  private function assign_record_id( $record_id )
  {
    $record = Participants_Db::get_participant( $record_id );
    
    if ( $record )
    {
      $this->record_id = $record_id;
    }
  }
  
  /**
   * build the relations array
   */
  private function build_relations()
  {
    foreach( $this->all_types() as $typename => $title )
    {
      $record_relations = new \pdbmrdb\store\get_related( $typename, $this->record_id );
      
      $relations_array = [];
      
      foreach( $record_relations->related_record_list() as $related_record_id )
      {
        $relations_array[ $related_record_id ] = \pdbmrdb\store\title::get_title( $typename, $related_record_id );
      }
      
      $this->relations[ $typename ] = $relations_array;
    }
  }
  
  /**
   * provides a list of all defined types
   * 
   * @return array $typename => $title
   */
  private function all_types()
  {
    $all_type_defs = \pdbmrdb\type\all_types::def_list();
    
    $all_types = [];
    
    foreach( $all_type_defs as $def )
    {
      /** @var \pdbmrdb\type\definition $def */
      
      if ( $def->is_relational() ) // include only relational types
      {
        $all_types[ $def->type_name() ] = $def->label_singular();
      }
    }
    
    return $all_types;
  }
}

This is meant to be installed as a plugin: How to Install a WordPress Plugin from a Gist

This class can be used in a PDB shortcode template or any custom code.