PostgreSQL允许将表的列定义为可变长度的多维数组。就像这样:
CREATE TABLE sal_emp
(
name text,
pay_by_quarter integer[],
schedule text[][]
);
以下是一些INSERT语句示例:
INSERT INTO sal_emp
VALUES ('Bill', '{10000, 10000, 10000, 10000}',
'{{"meeting", "lunch"}, {"training", "presentation"}}');
INSERT INTO sal_emp
VALUES ('Carol', '{20000, 25000, 25000, 25000}',
'{{"breakfast", "consulting"}, {"meeting", "lunch"}}');
SELECT * FROM sal_emp;
输出:
name | pay_by_quarter | schedule
-------+---------------------------+-------------------------------------------
Bill | {10000,10000,10000,10000} | {{meeting,lunch},{training,presentation}}
Carol | {20000,25000,25000,25000} | {{breakfast,consulting},{meeting,lunch}}
(2 rows)
我们如何在SQL Server或其任何替代品中实现相同的功能?
1:n
相关的边缘表中... 这个概念有一种懒散的味道 :-) - Shnugo