储存工作时间并有效查询的最佳方法

Question

我打算存储商店的工作时间。我想知道在工作时间字段中最好的建模方法是什么，这样我就可以以非常有效的方式获得当前时刻开/关商店的列表。

Answer 1

要存储正常的工作时间，您需要存储一些记录，其中包含：

• 商店-INTEGER
• DayOfWeek-整数（0-6）
• 营业时间-TIME
• 关闭时间-TIME

例如，我假设每个商店在国定假日减少工作时间或关闭工厂，因此您还需要存储一些替代记录：

• 商店-INTEGER
• OverrideStartDate-DATE
• OverrideEndDate-DATE
• DayOfWeek-整数（0-6）
• AltOpenTime-时间
• AltCloseTime-TIME
• 已关闭-INTEGER（0，1）

要找到开放式商店并不容易，但是您还需要检查是否有超车时间：

SELECT Shop
FROM OverrideHours
WHERE OverrideStartDate <= NOW()
AND OverrideEndDate >= NOW()
AND DayOfWeek = WEEKDAY(NOW())

如果返回任何记录，则这些商店将有其他时间或关闭。

您可以在此处执行一些不错的SQL-fu，但这为您提供了基础知识。

编辑

我还没有测试过，但这应该可以使您接近：

SELECT Normal.Shop
FROM Normal
LEFT JOIN Override
ON Normal.Shop = Override.Shop
AND Normal.DayOfWeek = Override.DayOfWeek
AND NOW() BETWEEN Override.OverrideStartDate AND Override.OverrideEndDate
WHERE Normal.DayOfWeek = WEEKDAY(NOW())
AND ((Override.Shop IS NULL AND TIME(NOW()) BETWEEN Normal.OpenTime AND Normal.CloseTime)
 OR  (Override.Shop IS NOT NULL AND Override.Closed <> 1 AND TIME(NOW()) BETWEEN Override.AltOpenTime AND Override.AltCloseTime))

编辑

至于效率，从某种意义上讲，它是高效的，您只需要对MySQL进行一次调用，而如果它是跨网络的，则通常是瓶颈。您必须进行测试，看看它是否符合您的规格。如果没有，您可能会玩一些索引。

编辑

测试。没有完成测试，但是有些。

mysql> select * from Normal;
+------+-----------+----------+-----------+
| Shop | DayOfWeek | OpenTime | CloseTime |
+------+-----------+----------+-----------+
|    1 |         1 | 09:00:00 | 17:00:00  | 
|    1 |         5 | 09:00:00 | 16:00:00  | 
|    2 |         1 | 09:00:00 | 17:00:00  | 
|    2 |         5 | 09:00:00 | 17:00:00  | 
+------+-----------+----------+-----------+
4 rows in set (0.01 sec)

mysql> select * from Override;
+------+-------------------+-----------------+-----------+-------------+--------------+--------+
| Shop | OverrideStartDate | OverrideEndDate | DayOfWeek | AltOpenTime | AltCloseTime | Closed |
+------+-------------------+-----------------+-----------+-------------+--------------+--------+
|    2 | 2010-12-01        | 2010-12-31      |         1 | 09:00:00    | 18:00:00     |      0 | 
|    2 | 2010-12-01        | 2010-12-31      |         5 | 09:00:00    | 18:00:00     |      0 | 
|    1 | 2010-12-01        | 2010-12-31      |         1 | 09:00:00    | 17:00:00     |      1 | 
+------+-------------------+-----------------+-----------+-------------+--------------+--------+
3 rows in set (0.00 sec)

mysql> SET @whenever = TIMESTAMP('2010-11-23 16:05');
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT WEEKDAY(@whenever);
+--------------------+
| WEEKDAY(@whenever) |
+--------------------+
|                  1 | 
+--------------------+
1 row in set (0.00 sec)

mysql> SELECT Normal.Shop FROM Normal LEFT JOIN Override ON Normal.Shop = Override.Shop AND Normal.DayOfWeek = Override.DayOfWeek AND @whenever BETWEEN Override.OverrideStartDate AND Override.OverrideEndDate WHERE Normal.DayOfWeek = WEEKDAY(@whenever) AND ((Override.Shop IS NULL AND TIME(@whenever) BETWEEN Normal.OpenTime AND Normal.CloseTime)  OR  (Override.Shop IS NOT NULL AND Override.Closed <> 1 AND TIME(@whenever) BETWEEN Override.AltOpenTime AND Override.AltCloseTime));
+------+
| Shop |
+------+
|    1 | 
|    2 | 
+------+
2 rows in set (0.00 sec)

mysql> SET @whenever = TIMESTAMP('2010-11-23 17:05');
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT Normal.Shop FROM Normal LEFT JOIN Override ON Normal.Shop = Override.Shop AND Normal.DayOfWeek = Override.DayOfWeek AND @whenever BETWEEN Override.OverrideStartDate AND Override.OverrideEndDate WHERE Normal.DayOfWeek = WEEKDAY(@whenever) AND ((Override.Shop IS NULL AND TIME(@whenever) BETWEEN Normal.OpenTime AND Normal.CloseTime)  OR  (Override.Shop IS NOT NULL AND Override.Closed <> 1 AND TIME(@whenever) BETWEEN Override.AltOpenTime AND Override.AltCloseTime));
Empty set (0.01 sec)

mysql> SET @whenever = TIMESTAMP('2010-12-25 16:05');
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT Normal.Shop FROM Normal LEFT JOIN Override ON Normal.Shop = Override.Shop AND Normal.DayOfWeek = Override.DayOfWeek AND @whenever BETWEEN Override.OverrideStartDate AND Override.OverrideEndDate WHERE Normal.DayOfWeek = WEEKDAY(@whenever) AND ((Override.Shop IS NULL AND TIME(@whenever) BETWEEN Normal.OpenTime AND Normal.CloseTime)  OR  (Override.Shop IS NOT NULL AND Override.Closed <> 1 AND TIME(@whenever) BETWEEN Override.AltOpenTime AND Override.AltCloseTime));
+------+
| Shop |
+------+
|    2 | 
+------+
1 row in set (0.00 sec)

mysql> SET @whenever = TIMESTAMP('2010-11-23 17:05');
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT WEEKDAY(@whenever);
+--------------------+
| WEEKDAY(@whenever) |
+--------------------+
|                  1 | 
+--------------------+
1 row in set (0.00 sec)

mysql> SELECT Normal.Shop FROM Normal LEFT JOIN Override ON Normal.Shop = Override.Shop AND Normal.DayOfWeek = Override.DayOfWeek AND @whenever BETWEEN Override.OverrideStartDate AND Override.OverrideEndDate WHERE Normal.DayOfWeek = WEEKDAY(@whenever) AND ((Override.Shop IS NULL AND TIME(@whenever) BETWEEN Normal.OpenTime AND Normal.CloseTime)  OR  (Override.Shop IS NOT NULL AND Override.Closed <> 1 AND TIME(@whenever) BETWEEN Override.AltOpenTime AND Override.AltCloseTime));
Empty set (0.00 sec)