create table event(
  xid int auto_increment not null,
  unique(xid),
  type varchar(32),
  subsystem tinytext,
  source_ipa tinytext,
  source_host text,
  source_user tinytext,
  target_host tinytext,
  target_ipa tinytext,
  target_user tinytext
);
alter table event add unique key (type,subsystem(16),source_ipa(32),source_host(32),source_user(16),target_host(32),target_ipa(32),target_user(16));
insert into event set type='legacy01',subsystem='',source_ipa='211.101.236.160',source_host='',source_user='',target_host='',target_ipa='',target_user='';
insert into event set type='legacy01',subsystem='',source_ipa='211.101.236.160',source_host='',source_user='',target_host='',target_ipa='',target_user='';