视图1： 基于 hr.tt union all scott.tt ---》 scott.ttt
视图2： 基于 视图1-》scott.ttt 创建 system.tt
问题再现：
SQL> create table hr.tt (a number);
Table created.
SQL> create table lixora.tt (a number);
Table created.
SQL> create view scott.tt as select * from hr.tt union all select * from lixora.tt;
View created.
SQL> create view system.tt as select * from scott.tt;
View created.
SQL> select * from system.tt
A
----------
1
更新视图2：
SQL> update system.tt set a=2;
update system.tt set a=2
*
ERROR at line 1:
ORA-01733: virtual column not allowed here
更新视图1：
SQL> update scott.tt set A=2;
update scott.tt set A=2
*
ERROR at line 1:
ORA-01732: data manipulation operation not legal on this view
SQL> !oerr ora 1732
| ORA-01733: virtual column not allowed here Cause: An attempt was made to use an INSERT, UPDATE, or DELETE statement on an expression in a view. Action: INSERT, UPDATE, or DELETE data in the base tables, instead of the view. |
总结：
无法对包括表达式的view 进行dml 操作