如果您正在使用复制(MySQL)，以下函数是不安全的，除非您正在使用基于行的复制。

USER(), CURRENT_USER() (or CURRENT_USER), UUID(), VERSION(), LOAD_FILE(), and RAND()

参见:http://dev.mysql.com/doc/refman/5.1/en/replication-features-functions.html

我想补充一点: 偏好“优雅”代码而不是高性能代码。在应用程序开发人员看来，对数据库最有效的代码通常是丑陋的。

Believing that nonsense about premature optimization. Databases must consider performance in the original design and in any subsequent development. Performance is 50% of database design (40% is data integrity and the last 10% is security) in my opinion. Databases which are not built from the bottom up to perform will perform badly once real users and real traffic are placed against the database. Premature optimization doesn't mean no optimization! It doesn't mean you should write code that will almost always perform badly because you find it easier (cursors for example which should never be allowed in a production database unless all else has failed). It means you don't need to look at squeezing out that last little bit of performance until you need to. A lot is known about what will perform better on databases, to ignore this in design and development is short-sighted at best.

将数据库仅仅视为一种存储机制(即美化的集合库)，因此从属于它们的应用程序(忽略其他共享数据的应用程序)

这之前已经说过了，但是:索引，索引，还是索引。我见过许多性能不佳的企业web应用程序，它们通过简单地进行一些分析(查看哪些表被频繁访问)，然后在这些表上添加索引来解决问题。这甚至不需要太多的SQL编写知识，而且回报是巨大的。

Avoid data duplication like the plague. Some people advocate that a little duplication won't hurt, and will improve performance. Hey, I'm not saying that you have to torture your schema into Third Normal Form, until it's so abstract that not even the DBA's know what's going on. Just understand that whenever you duplicate a set of names, or zipcodes, or shipping codes, the copies WILL fall out of synch with each other eventually. It WILL happen. And then you'll be kicking yourself as you run the weekly maintenance script.

最后:使用清晰、一致、直观的命名约定。与一段编写良好的代码应该是可读的一样，一个好的SQL模式或查询应该是可读的，并且实际上告诉您它在做什么，甚至没有注释。六个月后，当你不得不对桌子进行维护时，你会感谢自己的。“选择account_number, billing_date FROM national_accounts”比“选择ACCNTNBR, BILLDAT FROM NTNLACCTS”更容易使用。

I think the biggest mistakes that all developers and DBAs do is believing too much on conventions. What I mean by that is that convention are only guide lines that for most cases will work but not necessarily always. I great example is normalization and foreign keys, I know most people wont like this, but normalization can cause complexity and cause loss of performance as well, so if there is no reason to move a phone number to a phones table, don't do it. On the foreign keys, they are great for most cases, but if you are trying to create something that can work by it self when needed the foreign key will be a problem in the future, and also you loose performance. Anyways, as I sad rules and conventions are there to guide, and they should always be though of but not necessarily implemented, analysis of each case is what should always be done.

这里有一个视频链接，名为“经典数据库开发错误和克服它们的五种方法”，作者是Scott Walz