$bean-stored_fetched_row_c, logic hooks and relate fields

Question

Im trying to detect a change in a relationship through a logic hook but I cant seem to get the old value to compare it to the new. 
 I have a serial number module which has a relationship to accounts 
 Accounts -> one-to-many -> S_SerialNumber 
 this is visible in my module view and i can get the relationship data if i query the S_SerialNumber 
 "accounts_s_serialnumber_1_name": "ID Print",
 "accounts_s_serialnumber_1": {
 "name": "ID Print",
 "id": "cac71e64-7c2c-11eb-9bf6-066c2def7d44",
 "_acl": {
 "fields": {
 "business_center_name": {
 "create": "no",
 "write": "no",
 "license": "no"
 },
 "business_center_id": {
 "create": "no",
 "write": "no",
 "license": "no"
 }
 },
 "_hash": "e376f7492abb281a71d6a0860441877a"
 }
 },
 "accounts_s_serialnumber_1accounts_ida": "cac71e64-7c2c-11eb-9bf6-066c2def7d44", 
 the problem I'm having is I want to detect if this relationship is changed on an after_save logic hook 
 My before_save hook captures the data with the 
 public function get_record($bean, $event, $arguments)
 {
 $bean->stored_fetched_row_c = $bean->fetched_row;
 } 
 However $bean->fetched_row does not include the relationship data for me to then compare 
 If I use the $bean->load_relationship() it only gets the updated data 
 Anybody know how you compare a relationship between a before and after save logic hook?

john Fieldsend · Accepted Answer

Hello john, exist a var for relationship fields into SugarBean 
 I'm been using into before_save LH the Related Module, for example: 
 if (
 $args['isUpdate'] == 1
 && !empty($bean->rel_fields_before_value[$idrel])
 && $bean->$idrel != $bean->rel_fields_before_value[$idrel]
) { 
 In this code $idrel is the value the "join_key_lhs", this value can be found in the php file of the relationship between the Accounts and your custom module. 
 The directory where you find the metadata is: "custom/metadata/*.php" 
 The file has this structure: 
 <?php
// created: 2020-12-03 15:33:40
$dictionary["accounts_opportunities_1"] = array (
 'true_relationship_type' => 'one-to-many',
 'from_studio' => true,
 'relationships' => 
 array (
 'accounts_opportunities_1' => 
 array (
 'lhs_module' => 'Accounts',
 'lhs_table' => 'accounts',
 'lhs_key' => 'id',
 'rhs_module' => 'Opportunities',
 'rhs_table' => 'opportunities',
 'rhs_key' => 'id',
 'relationship_type' => 'many-to-many',
 'join_table' => 'accounts_opportunities_1_c',
 'join_key_lhs' => 'accounts_opportunities_1accounts_ida',
 'join_key_rhs' => 'accounts_opportunities_1opportunities_idb',
 ),
 ),
 'table' => 'accounts_opportunities_1_c',
 'fields' => 
 array (
 'id' => 
 array (
 'name' => 'id',
 'type' => 'id',
 ),
 'date_modified' => 
 array (
 'name' => 'date_modified',
 'type' => 'datetime',
 ),
 'deleted' => 
 array (
 'name' => 'deleted',
 'type' => 'bool',
 'default' => 0,
 ),
 'accounts_opportunities_1accounts_ida' => 
 array (
 'name' => 'accounts_opportunities_1accounts_ida',
 'type' => 'id',
 ),
 'accounts_opportunities_1opportunities_idb' => 
 array (
 'name' => 'accounts_opportunities_1opportunities_idb',
 'type' => 'id',
 ),
 ),
 'indices' => 
 array (
 0 => 
 array (
 'name' => 'idx_accounts_opportunities_1_pk',
 'type' => 'primary',
 'fields' => 
 array (
 0 => 'id',
 ),
 ),
 1 => 
 array (
 'name' => 'idx_accounts_opportunities_1_ida1_deleted',
 'type' => 'index',
 'fields' => 
 array (
 0 => 'accounts_opportunities_1accounts_ida',
 1 => 'deleted',
 ),
 ),
 2 => 
 array (
 'name' => 'idx_accounts_opportunities_1_idb2_deleted',
 'type' => 'index',
 'fields' => 
 array (
 0 => 'accounts_opportunities_1opportunities_idb',
 1 => 'deleted',
 ),
 ),
 3 => 
 array (
 'name' => 'accounts_opportunities_1_alt',
 'type' => 'alternate_key',
 'fields' => 
 array (
 0 => 'accounts_opportunities_1opportunities_idb',
 ),
 ),
 ),
); 
 
 Kind Regards

john Fieldsend · Answer

Hi John,
Is the objective to track changes to this field? If so, does the standard Audit log not provide a desirable solution?
https://support.sugarcrm.com/Knowledge_Base/User_Interface/Historical_Summary_vs._Activity_Stream_vs._Change_Log/

There is also a method using calculated fields with example by Sugar knowledgebase here:
https://support.sugarcrm.com/Knowledge_Base/Studio_and_Module_Builder/Sugar_Logic/Sugar_Logic_Walkthrough_Tracking_a_Fields_History/

$bean->stored_fetched_row_c, logic hooks and relate fields