Postgres 编码数据查找表

Question

我有很多已编码的数据，我正在尝试制作查找表来添加代码的描述。如果设置了主键和外键，是否可以让查询自动返回查找表描述，或者您总是必须在查询中使用联接？这是我现在用来测试第一个查找表的两个表。

Table "public.severity_lookup"
    Column     |         Type          | Collation | Nullable | Default
---------------+-----------------------+-----------+----------+---------
 severity      | character varying(1)  |           | not null |
 severity_desc | character varying(30) |           |          |
Indexes:
    "pk_severity_lookup" PRIMARY KEY, btree (severity)
Referenced by:
    TABLE "crashes" CONSTRAINT "fk_crashes_severity" FOREIGN KEY (severity) REFERENCES severity_lookup(severity)




Table "public.crashes"
          Column           |          Type          | Collation | Nullable | Default
---------------------------+------------------------+-----------+----------+---------
 crash_id                  | character varying(31)  |           |          |
...
severity                  | character varying(1)   |           |          |
Foreign-key constraints:
    "fk_crashes_severity" FOREIGN KEY (severity) REFERENCES severity_lookup(severity)

（我缩写了崩溃表，因为它很长）

Here is the data in the severity_lookup table:
 SELECT * FROM severity_lookup;
 severity |    severity_desc
----------+----------------------
 F        | Fatality
 I        | Injury
 P        | Property Damage Only
(3 rows)

也许我想做的事情是不可能的，但我一直在四处寻找，但没有找到任何关于它的好信息。如果有人知道有关 SQL/postgres 中查找表的资源/教程，我将不胜感激。

Answer 1

对于上面的以下问题，为了能够查找两个表的数据，您可以创建连接两个表并返回描述和编码数据的视图，创建视图的示例查询如下：

CREATE VIEW crashes_with_descriptions AS
SELECT c.crash_id, c.severity, sl.severity_desc
FROM crashes c
JOIN severity_lookup sl ON c.severity = sl.severity;

创建视图后，您可以使用以下命令查询上述视图：

SELECT * FROM crashes_with_descriptions;

上面的查询将返回包含 crash_id、严重性和严重性_desc 的结果集。