ORA-01733: virtual column not allowed here

 基表： hr.tt  scott.tt
 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