利用物化视图刷数据

1、创建测试表
SQL> CREATE TABLE t_M
2 AS
3 SELECT * FROM all_objects;

Table created

2、查询测试表中记录
SQL> select count(*) from t_m;

COUNT(*)
———-
48941

3、创建中间表
SQL> create table t_m_n as
2 select * from t_m where 1=0;

Table created

4、查询中间表记录
SQL> select count(*) from t_m_n;

COUNT(*)
———-
0

5、创建刷新物化视图
SQL> CREATE MATERIALIZED VIEW t_m_n
on prebuilt TABLE WITH REDUCED PRECISION
REFRESH FORCE
ON DEMAND
AS
SELECT * FROM t_m;

Materialized view created

6、执行物化视图刷新
SQL> exec dbms_mview.refresh(‘T_M_N’);

PL/SQL procedure successfully completed

7、查询物化视图中记录数
SQL> select count(*) from t_m_n;

COUNT(*)
———-
48941

8、删除物化视图
SQL> DROP MATERIALIZED VIEW T_M_N;

Materialized view dropped

9、查询中间表中条数
SQL> select count(*) from t_m_n;

COUNT(*)
———-
48941

10、后续可能操作
1）t_m和t_m_n相互重命名，实现在线修移动表的位置、改表结构、降低高水位等操作，同（shrink）
2）和dblink结合，实现数据的跨版本迁移