如何使用PostgreSQL在视图定义中保留注释？

Question

当我从复杂查询创建视图时,我需要保留我在SQL查询中添加的注释,以便更容易地返回到视图定义.在pgAdminIII中,当我创建一个视图然后查阅视图定义时,注释被删除并且缩进完全修改了......有没有办法改变这种行为？

查看创建:

CREATE OR REPLACE VIEW public.v_test AS 

-- Count number of null lines within table 'test'
(SELECT * FROM public.test WHERE client IS NULL);

创建后查看定义,如pgAdminIII中所示:

-- View: v_test

-- DROP VIEW v_test;

CREATE OR REPLACE VIEW v_test AS 
 SELECT test.gid,
    test.client
   FROM test
  WHERE test.client IS NULL;

ALTER TABLE v_test
  OWNER TO postgres;

感谢帮助!

Answer 1

不,Postgres将视图保存为解析树,因此它不记得空格或注释.

但是,如果你真的需要它,functions可以记住评论.

Answer 2

Postgres不会按原样存储视图定义,因此您无法以这种方式存储注释.使用comment命令:

create view my_view as select 1;
comment on view my_view is 'It is my view';

select obj_description('my_view'::regclass);

 obj_description 
-----------------
 It is my view
(1 row)

你可以在PgAdmin3中看到评论:

-- View: public.my_view

-- DROP VIEW public.my_view;

CREATE OR REPLACE VIEW public.my_view AS 
 SELECT 1;

ALTER TABLE public.my_view
  OWNER TO postgres;
COMMENT ON VIEW public.my_view
  IS 'it is my view';