oracle - 当行表列大小更改时，如何更改物化 View 列大小？

Question

当行表列大小更改时，如何更改物化 View 列大小？这是Linux 上的oracle 11gR2 db。我尝试重新编译MV，但没有成功。请不要将此问题自动迁移到另一个数据库站点，我想留在 stackoverflow 中。谢谢!

Answer 1

如果更改表，则还必须更改物化 View 。

--Create simple table and materialized view
create table test1(a varchar2(1 char));
create materialized view mv_test1 as select a from test1;

--Increase column width of column in the table
alter table test1 modify (a varchar2(2 char));

--Insert new value that uses full size
insert into test1 values('12');

--Try to compile and refresh the materialized view
alter materialized view mv_test1 compile;
begin
    dbms_mview.refresh(user||'.MV_TEST1');
end;
/

ORA-12008: error in materialized view refresh path
ORA-12899: value too large for column "JHELLER"."MV_TEST1"."A" (actual: 2, maximum: 1)
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2563
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2776
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2745
ORA-06512: at line 3

--Increase column width of column in the materialized view and refresh
alter materialized view mv_test1 modify (a varchar2(2 char));
begin
    dbms_mview.refresh(user||'.MV_TEST1');
end;
/
select * from mv_test1;
A
--
12