Master表字段扩张时的对应方法

如果Master表的数据量很大，Master表中的列，宽度扩张了，MVIEW表如何对应处理？ 此时，重建MVIEW可能会耗费很长的时间。 可以采用 alter materialized view modify 的方式来进行。不过，没有官方文档支持。 create table TEST(id integer, TEST_NUMBER NUMBER(18,6)); insert into TEST  select i+j, i+j    from  (           with DATA2(j) as (                             select 0 j from DUAL                               union all                             select j+1000 from DATA2 where j < 999000                            )           select j from DATA2          ),          (           with DATA1(i) as (                             select 1 i from DUAL                               union all                             select i+1 from DATA1 where i < 1000                            )           select i from DATA1          ); ALTER TABLE TEST ADD CONSTRAINT PK_TEST PRIMARY KEY(ID); CREATE MATERIALIZED VIEW LOG ON TEST; CREATE MATERIALIZED VIEW MV_TEST REFRESH FAST AS SELECT * FROM TEST;

set timing on

如果Master表的字段扩张了 ，可以在MVIEW对应的字段也扩张：

SQL> ALTER MATERIALIZED VIEW MV_TEST MODIFY (TEST_NUMBER NUMBER(22,6)); time elapsed: 00:00:00.08

扩张后确认:

SQL> exec dbms_mview.refresh('MV_TEST'); SQL> exec dbms_mview.refresh('MV_TEST','C');

本文转自健哥的数据花园博客园博客，原文链接：http://www.cnblogs.com/gaojian/p/3_15561107161.html，如需转载请自行联系原作者