獲取所有具有外鍵約束的列名

Question

我正在使用 PostgreSQL。 我想編寫一個查詢，返回所有具有外鍵約束的列名以及它們引用的這些列的表名。

Answer 1

據我所知， information_schema視圖沒有給你列名，所以你必須使用目錄：

SELECT c.conrelid::regclass AS source_table,
       a.attname AS column_name,
       k.n AS position,
       c.confrelid::regclass AS referenced_table
FROM pg_constraint AS c
   CROSS JOIN LATERAL unnest(c.conkey) WITH ORDINALITY AS k(attnum, n)
   JOIN pg_attribute AS a
      ON k.attnum = a.attnum AND c.conrelid = a.attrelid
WHERE c.contype = 'f'
ORDER BY c.conrelid::regclass::text, k.n;

要僅獲取特定表的數據，請將以下內容添加到WHERE條件：

AND c.conrelid = 'mytable'::regclass