是否有一种方法使用SQL列出给定表的所有外键?我知道表名/模式,我可以把它插入。


当前回答

PSQL就是这样做的,如果你用:

psql -E

它将准确地显示执行了哪些查询。在查找外键的情况下,它是:

SELECT conname,
  pg_catalog.pg_get_constraintdef(r.oid, true) as condef
FROM pg_catalog.pg_constraint r
WHERE r.conrelid = '16485' AND r.contype = 'f' ORDER BY 1

在这种情况下,16485是我正在寻找的表的oid -你可以通过将你的表名转换为regclass来获得它:

WHERE r.conrelid = 'mytable'::regclass

如果表名不是唯一的(或者是搜索路径中的第一个),则对表名进行模式限定:

WHERE r.conrelid = 'myschema.mytable'::regclass

其他回答

我创建了一个小工具来查询和比较数据库模式: Dump PostgreSQL数据库模式到文本

有关于FK的信息,但ollyc的回复提供了更多的细节。

SELECT conrelid::regclass AS table_name, 
       conname AS foreign_key, 
       pg_get_constraintdef(oid) 
FROM   pg_constraint 
WHERE  contype = 'f' 
AND    connamespace = 'public'::regnamespace   
ORDER  BY conrelid::regclass::text, contype DESC;

https://soft-builder.com/how-to-list-all-foreign-keys-in-postgresql-database

你可以使用PostgreSQL系统目录。也许您可以查询pg_constraint来请求外键。 您还可以使用信息模式

扩展到ollyc配方:

CREATE VIEW foreign_keys_view AS
SELECT
    tc.table_name, kcu.column_name,
    ccu.table_name AS foreign_table_name,
    ccu.column_name AS foreign_column_name
FROM
    information_schema.table_constraints AS tc
    JOIN information_schema.key_column_usage 
        AS kcu ON tc.constraint_name = kcu.constraint_name
    JOIN information_schema.constraint_column_usage 
        AS ccu ON ccu.constraint_name = tc.constraint_name
WHERE constraint_type = 'FOREIGN KEY';

然后:

SELECT * FROM foreign_keys_view WHERE table_name='YourTableNameHere';

为了扩展Martin的精彩回答,这里有一个查询,它允许您根据父表进行过滤,并显示每个父表的子表的名称,以便您可以根据父表中的外键约束查看所有依赖的表/列。

select 
    con.constraint_name,
    att2.attname as "child_column", 
    cl.relname as "parent_table", 
    att.attname as "parent_column",
    con.child_table,
    con.child_schema
from
   (select 
        unnest(con1.conkey) as "parent", 
        unnest(con1.confkey) as "child", 
        con1.conname as constraint_name,
        con1.confrelid, 
        con1.conrelid,
        cl.relname as child_table,
        ns.nspname as child_schema
    from 
        pg_class cl
        join pg_namespace ns on cl.relnamespace = ns.oid
        join pg_constraint con1 on con1.conrelid = cl.oid
    where  con1.contype = 'f'
   ) con
   join pg_attribute att on
       att.attrelid = con.confrelid and att.attnum = con.child
   join pg_class cl on
       cl.oid = con.confrelid
   join pg_attribute att2 on
       att2.attrelid = con.conrelid and att2.attnum = con.parent
   where cl.relname like '%parent_table%'