psql表描述

Question

在psql中，如果我做了\d+，我会得到以下内容

 Schema |          Name           |   Type   | Owner  |    Size    |     Description 
--------+-------------------------+----------+--------+------------+-------------
 norsar | Routing Result          | table    | morten | 16 kB      | 
 norsar | Routing Result_id_seq   | sequence | morten | 8192 bytes | 

诸若此类。最后一个字段“描述”总是空白的。该字段在哪里读取其内容？-因此，我如何在表上设置描述？在某些情况下，这是非常有用的--如果我执行\d+ <tablename>，在列上显示的描述也是一样的。

我试过\set ECHO_HIDDEN ON，但这并没有让它变得更清楚。

Answer 1

它显示了使用命令comment on定义的注释：

下表定义：

create table foo
(
  id integer primary key, 
  name text not null
);

comment on table foo is 'This is the famous foo table';
comment on column foo.id is 'This is the primary key';
comment on column foo.name is 'This is the name of the thing';

然后就会像这样出现：

postgres> \d+
                                List of relations
 Schema |   Name    | Type  | Owner  |    Size    |         Description
--------+-----------+-------+--------+------------+------------------------------
 public | foo       | table | thomas | 8192 bytes | This is the famous foo table
(1 row)

postgres> \d+ foo
                                             Table "public.foo"
 Column |  Type   | Collation | Nullable | Default | Storage  | Stats target |          Description
--------+---------+-----------+----------+---------+----------+--------------+-------------------------------
 id     | integer |           | not null |         | plain    |              | This is the primary key
 name   | text    |           | not null |         | extended |              | This is the name of the thing
Indexes:
    "foo_pkey" PRIMARY KEY, btree (id)


postgres>