Created by Jerry Wang, last modified on Apr 08, 2014
在ui上删除一个attachment时,
会call到function module CRM_KW_OBJECT_EXISITENCE_CHECK 检查该product是否在DB存在:
如果product在DB存在,则product和attachment的link关系的deletion立即生效,无需COMMIT WORK,否则deletion发生在COMMIT WORK时。
如果新建一个product,再上传一个attachment,然后立即删除:
Attachment component controller的save方法会间接的trigger COMMIT WORK:
进而调用注册在COMMIT上的subroutine TRIGGER_LINK_EVENT: