database - 数据库设计中的陷阱

Question

我需要为某个地方设计一个数据库。我有以下实体：'food' -> foodId, foodName 'consumers'-> c_Id,cBreakfast,cLunch,cDinner 消费者吃了三顿。早餐、午餐和晚餐，这些字段从带有其 ID 的“食物”实体中获取食物。但最终我会落入陷阱。我不能把它分成三餐早餐、午餐和晚餐呢。什么样的设计更适合这个问题？

Answer 1

下面的模式可以让你跟踪谁吃了什么，吃了哪顿饭。在我的示例中，您可以看到 Bob 早餐吃煎蛋卷，午餐吃沙拉，晚餐吃牛排。玛丽错过了早餐，午餐吃了牛排，晚餐吃了沙拉。

consumers
    id              unsigned int(P)
    name            varchar(30)

+----+------+
| id | name |
+----+------+
|  1 | Bob  |
|  2 | Mary |
| .. | .... |
+----+------+

consumptions
    id              unsigned int(P)
    consumer_id     unsigned int(F consumers.id)
    mealtime_id     unsigned int(F mealtimes.id)
    food_id         unsigned int(F foods.id)

+----+-------------+-------------+---------+
| id | consumer_id | mealtime_id | food_id |
+----+-------------+-------------+---------+
|  1 |           1 |           1 |       1 |
|  2 |           1 |           2 |       2 |
|  3 |           1 |           3 |       3 |
|  4 |           2 |           2 |       3 |
|  5 |           2 |           3 |       2 |
| .. | ........... | ........... | ....... |
+----+-------------+-------------+---------+

foods
    id              unsigned int(P)
    name            varchar(20)

+----+--------+
| id | name   |
+----+--------+
|  1 | Omelet |
|  2 | Salad  |
|  3 | Steak  |
| .. | ...... |
+----+--------+

mealtimes
    id              unsigned int(P)
    name            varchar(10)

+----+-----------+
| id | name      |
+----+-----------+
|  1 | Breakfast |
|  2 | Lunch     |
|  3 | Dinner    |
| .. | ......... |
+----+-----------+