CRM/ActivityActivityContactcivicrm_activity_contactActivity Contacttrue4.4true id int unsigned true Activity contact id Number 4.4 id true activity_id int unsigned true Foreign key to the activity for this record. Activity 4.4 activity_id civicrm_activity id 4.4 CASCADE contact_id true int unsigned true Foreign key to the contact for this record. Contact 4.4 contact_id civicrm_contact id 4.4 CASCADE record_type_id int unsigned Determines the contact's role in the activity (source, target, or assignee). activity_contacts Select Contact Role 4.4 UI_activity_contact contact_id activity_id record_type_id true 4.4 index_record_type activity_id record_type_id 4.4