更改Oracle类型

最近版本的Oracle允许更改一个类型而无需重建，如下：

create type T1 as object ( x number, y number ) not final;

/

 

Type created.

 

create type T2 as table of T1;

/

 

Type created.

 

create or replace type T1 as object ( x number, y number, z number );

/

create or replace type T1 as object ( x number, y number, z number );

*

ERROR at line 1:

ORA-02303: cannot drop or replace a type with type or table dependents

需要做的仅仅是ALTER TYPE：

alter type T1 add attribute ( z number );

alter type T1 add attribute ( z number )

*

ERROR at line 1:

ORA-22312: must specify either CASCADE or INVALIDATE option

 

alter type T1 add attribute ( z number ) cascade;

 

Type altered.