Question

假设我有一个包含supplierID的供应商表和另外14列。我想获得供应商的任何列都是fk的所有表的列表。

我有以下查询，它从supplier.supplierID获取包含FK的所有表：

select (select r.relname from pg_class r where r.oid = c.conrelid) as table, 
    (select r.relkind from pg_class r where r.oid = c.conrelid) as type,
       (select array_agg(attname) from pg_attribute 
        where attrelid = c.conrelid and ARRAY[attnum] <@ c.conkey) as col, 
       (select r.relname from pg_class r  where r.oid = c.confrelid) as ftable,
    (select n.nspname from pg_class r left join pg_namespace n on r.oid=n.oid where r.oid = n.oid) as schema
from pg_constraint c 
where c.confrelid = (select oid from pg_class where relname = 'supplier') and 
      c.confkey @> (select array_agg(attnum) from pg_attribute 
                    where attname = 'supplierID ' and attrelid = c.confrelid);

这是不完整的，因为我需要知道供应商中的所有列，其中任何一个都可以是其他地方的FK（假设所有列都是唯一的）。

有没有办法改善我的查询？我讨厌在所有列上运行它15个项目。

Answer 1

您可以查看以下查询，看看它是否提供了所需的结果

SELECT mytable.table_name AS mytablename, kcu.column_name AS mycolumns, allforeignkey.table_name AS referredtable, allforeignkey.column_name AS referredcolumn

FROM  information_schema.table_constraints AS mytable

JOIN (

  SELECT table_name,column_name,unique_constraint_name FROM  information_schema.referential_constraints

  INNER JOIN information_schema.key_column_usage AS kcu ON information_schema.referential_constraints.constraint_name = kcu.constraint_name

  ) AS allforeignkey ON mytable.constraint_name = allforeignkey.unique_constraint_name

INNER JOIN information_schema.key_column_usage AS kcu ON mytable.constraint_name = kcu.constraint_name

WHERE mytable.constraint_type = 'UNIQUE' AND mytable.table_name = 'your_table_name';

基本上我正在做的是我获取了指定表的所有UNIQUE列，然后是数据库中所有外键的列表并加入结果，这将给出UNIQUE列已在其他表格中引用

Postgresql如何将所有表链接到另一个表？

1 个答案: