我有企業和DOMAINS表。每個企業的財產是它應該有一個主域,但它可以有多個域。我想出了這個表結構標誌列或外鍵?
+---------------------------------------+
| ENTERPRISES |
+----+--------------+-------------------+
| ID | Name | Primary Domain ID |
+----+--------------+-------------------+
| 1 | Enterprise A | 2 |
| 2 | Enterprise B | 4 |
+----+--------------+-------------------+
+---------------------------------------+
| DOMAINS |
+----+------------------+---------------+
| ID | Domain Name | Enterprise ID |
+----+------------------+---------------+
| 1 | ent-a.com | 1 |
| 2 | enterprise-a.com | 1 |
| 3 | ent-b.com | 2 |
| 4 | enterprise-b.com | 2 |
+----+------------------+---------------+
我的同事認爲這種替代結構:
+-------------------+
| ENTERPRISES |
+----+--------------+
| ID | Name |
+----+--------------+
| 1 | Enterprise A |
| 2 | Enterprise B |
+----+--------------+
+----------------------------------------------------+
| DOMAINS |
+----+------------------+---------------+------------+
| ID | Domain Name | Enterprise ID | Is Primary |
+----+------------------+---------------+------------+
| 1 | ent-a.com | 1 | False |
| 2 | enterprise-a.com | 1 | True |
| 3 | ent-b.com | 2 | False |
| 4 | enterprise-b.com | 2 | True |
+----+------------------+---------------+------------+
我的問題是,哪一個更有效/正確的嗎?
此外,在第一個示例中,我應該使用ID作爲主域列還是字符串值,因此ENTERPRISES表對DOMAINS表沒有循環依賴關係?