sql - 我们可以在 PostgreSql 中向类型表添加列吗？

Question

创造了一种类型的车辆——

create type vehicle as ( tag text, name text);

使用类型创建表 -

create table bike of vehicle;

尝试将列添加为-

alter table bike add column attributes text;
ERROR:  cannot add column to typed table

是否可以通过任何方法在类型列中添加列？

Answer 1

来自 ALTER TYPE 的文档

CASCADE
Automatically propagate the operation to typed tables of the type being altered, and their descendants.

因此，使用您的示例:

CREATE TYPE vehicle AS ( tag text, name text);
CREATE TABLE bike OF vehicle;
INSERT INTO bike(tag, name) values ('t','n')
ALTER TYPE vehicle ADD ATTRIBUTE test text CASCADE;
SELECT * FROM bike

结果是:

|tag|name|test|
|---|----|----|
|t  |n   |    |