與SQL中外鍵的關係？

Question

我翻譯的模式，以SQL遞歸關係，我想在一個表中引用兩列，一列在另一個表 架構是如下：

Table: Request 
(
    mem_id1, 
    mem id2, 
    approved 
) 

所需的外鍵：

request.mem_id1 will reference member.mem_id 
request.mem_id2 will reference member.mem_id 

我曾嘗試以下：

CREATE TABLE members (
mem_id INTEGER, 
f_name VARCHAR(10), 
l_name VARCHAR(10), 
address VARCHAR(40), 
name VARCHAR(20), 
domain VARCHAR(15), 
PRIMARY KEY(mem_id) 
) 

CREATE TABLE member_phone (
mem_id INTEGER, 
phone_no INTEGER, 
PRIMARY KEY (mem_id,phone_no), 
FOREIGN KEY (mem_id) REFERENCES members (mem_id) 
) 

CREATE TABLE request (
mem_id1 INTEGER, 
mem_id2 INTEGER, 
approved BIT(1), 
PRIMARY KEY (mem_id1,mem_id2), 
FOREIGN KEY (mem_id1,mem_id2) REFERENCES members (mem_id) 
) 

Answer 1

我相信你想兩個獨立的外鍵：

CREATE TABLE request (
mem_id1 INTEGER, 
mem_id2 INTEGER, 
approved BIT(1), 
PRIMARY KEY (mem_id1, mem_id2), 
FOREIGN KEY (mem_id1) REFERENCES members (mem_id), 
FOREIGN KEY (mem_id2) REFERENCES members (mem_id) 
)