This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=XR6Ycdecf2Y&list=PLVsNizTWUw7HhYtI-4GGmlJ5yxNdwNI_X ================================================================================ Trigger: the code which is attached onto table, and when table runs tasks with "insert, update, delete", that code is executed ================================================================================ When member unregisters (delete trigger), that member is also managed in "unregistered table" (by copying the information from original table) ================================================================================ update check the manipulated record delete record ================================================================================ create deletedMemberTBL ================================================================================ create trigger ================================================================================ delete record ================================================================================ Backup ================================================================================ ================================================================================ ================================================================================ ================================================================================ ================================================================================ To create one file, select this option ================================================================================ ================================================================================ restore backup