1.创建一个复合类型，重命名复合类型，为复合类型增加属性、删除属性

postgres=# create type type1 as (t1 int, t2 text);
postgres=# alter type type1 rename to type_1;
postgres=# alter type type_1 add attribute t3 float;
postgres=# alter type type_1 drop attribute t1;

2.创建一个枚举类型，新增标签值，重命名标签值

postgres=# create type type2 as enum('open','close');
postgres=# alter type type2 add value if not exists 'unknow' before 'close';
postgres=# alter type type2 rename value 'close' to 'closed';

3.使用新创建的类型创建表

postgres=# create table dogs(t1 type_1, t2 type2);

4.删除类型

postgres=# drop type type_1 cascade ;
postgres=# drop table dogs ;
postgres=# drop type type2 ;