PostgreSQL查看表的主外键等约束关系代码解析

本篇文章小编给大家分享一下PostgreSQL查看表的主外键等约束关系代码解析，文章代码介绍的很详细，小编觉得挺不错的，现在分享给大家供大家参考，有需要的小伙伴们可以来看看。

代码如下：

SELECT
   tc.constraint_name, tc.table_name, kcu.column_name, 
   ccu.table_name AS foreign_table_name,
   ccu.column_name AS foreign_column_name,
   tc.is_deferrable,tc.initially_deferred
 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' AND tc.table_name = 'your table name';

constraint_type有四种：

UNIQUE、PRIMARY KEY、CHECK、FOREIGN KEY

通过修改上边sql语句的table_name和constraint_type来进行相应的查询