在数据库中存储行数或动态获取

Say I have a table full of comments, each from different users, and I want to count how many comments each user has. Should I have a separate table with the count, and update that on creation/deletion of comments, or should I query the count every time?

假设我有一个满是评论的表，每个都来自不同的用户，我想计算每个用户有多少评论。我应该在创建/删除注释时使用一个单独的计数表，并对其进行更新，还是应该每次都查询计数?

I feel like the latter is better, but I want some more experienced input on the matter. Thanks.

我觉得后者更好一些，但我希望在这个问题上有更多的经验。谢谢。

3 个解决方案

#1

Following the good old YAGNI principle, I would suggest you go with the simplest solution for now, which is just counting the number of comments as needed. This is just pragmatic coding.

遵循古老的YAGNI原则，我建议您暂时使用最简单的解决方案，即根据需要计算注释的数量。这只是一种实用的编码。

If, down the line, you find this is causing even small performance problems, then you should replace it with a cached value using a stored procedure or similar, but chances are it will serve you just fine.

如果您最终发现这甚至会导致很小的性能问题，那么您应该使用存储过程或类似的方法将其替换为缓存值，但它很可能会很好地为您服务。

So, I realise this probably isn't the clear answer you want, but: if you're making something small, go with the easy solution (counting); if you're making something bigger, go with the easy solution (counting) then upgrade to the harder solution (storing a value) if you find you need it. If you know what you're making is guaranteed to be big (lucky you!) then fine, go straight for the harder solution.

所以，我意识到这可能不是你想要的明确答案，但是:如果你正在做一个小的事情，就用简单的解决方案(计数);如果你正在做一些更大的事情，选择简单的解决方案(计数)，然后升级到更难的解决方案(存储一个值)，如果你发现你需要它。如果你知道你正在做的东西一定会很大(幸运的是你!)，那好吧，直接去找更难的解决方案。

Note: I've said "harder solution" but as you probably know it's only fractionally harder than the easy solution.

注意:我说过“更难的解决方案”，但是你可能知道，它只比简单的解决方案稍微难一点。

3 个解决方案

#1

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