文档解释
ORA-39301: Cannot alter values recorded in materialized view log: string
Cause: DBMS_METADATA_DIFF was comparing two materialized view logs that are recording different values, and the set of values in the first materialized view log cannot be changed to that in the second materialized view log. The error message identifies the specific problem.
Action: The difference cannot be eliminated with an SQL ALTER statement.
ORA-39301：代表着不能改变记录在材质视图Log当中的值。
官方解释
常见案例
一般处理方法及步骤
1. 如果你的表修改对材质视图Log没有任何影响，那么，表的更改将会按照正常的方式被保存和验证，从而不会引发错误。
2. 如果你需要修改表结构，而此表正在材质视图Log的视图中被使用，你可以临时关闭材质视图Log，从而允许修改表结构，在修改表之后再把它重新开启，而完成材质视图Log的更新。
