更复杂的是，这样的触发逻辑可能很快就会变得太复杂，我们最终可能会决定在某个时候触发完全刷新这样的解决方案。@MarkBarinstein同意，不幸的是，DB2fori不支持系统维护的MQT。但是，如果您需要对MQT进行实时更新，那么更新MQT的触发器是唯一

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更复杂的是，这样的触发逻辑可能很快就会变得太复杂，我们最终可能会决定在某个时候触发完全刷新这样的解决方案。@MarkBarinstein同意，不幸的是，DB2fori不支持系统维护的MQT。但是，如果您需要对MQT进行实时更新，那么更新MQT的触发器是唯一的选项。如果不需要实时，则可以进行计划刷新（使用刷新语句或用户程序）。让触发器使用刷新命令没有意义。

REFERENCING OLD TABLE AS ___
            NEW TABLE AS ___

create table test (id int not null primary key, a int)@
create table test_mqt (cnt) as (select sum(a) from test) data initially deferred refresh deferred maintained by user@

insert into test values (1, 1), (2, 1), (3, 1) with nc@

create or replace trigger test_aus 
after update on test
referencing 
new table as n
old table as o
for each statement
mode db2sql
begin atomic
  if (exists (select 1 from n,o where n.id=o.id and n.a<>o.a)) then
    refresh table test_mqt;
  end if;
end@

-- trigger IS NOT fired after the following update
update test set a=1 with nc@
-- the following select returns 0
select cnt from test_mqt@

-- trigger IS fired after the following update
update test set a=2 with nc@
-- the following select returns 6
select cnt from test_mqt@

create or replace trigger test_aus 
after update on test
referencing 
new row as n
old row as o
for each row
mode db2sql
begin atomic
  if n.a <> o.a then
    update test_mqt set cnt = cnt + n.a - o.a;
  end if;
end@

after update of a on test 
for each row 

create or replace trigger test_aus 
after update on test
referencing 
new table as n
old table as o
for each statement
mode db2sql
begin atomic
   update test_mqt 
     set cnt = cnt + (select sum(n.a - o.a) 
                        from N join O using(id)
                        where n.a <> o.a
                      );

end@

CREATE ENCODED VECTOR INDEX sales_fact_location_id_evi 
ON sales_fact(sale_location_id ASC) 
INCLUDE(SUM(sale_amount_measure))