应用程序开发人员常见的数据库开发错误有哪些?


当前回答

根据我的经验: 不与有经验的dba沟通。

其他回答

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.

开发人员所犯的关键数据库设计和编程错误

Selfish database design and usage. Developers often treat the database as their personal persistent object store without considering the needs of other stakeholders in the data. This also applies to application architects. Poor database design and data integrity makes it hard for third parties working with the data and can substantially increase the system's life cycle costs. Reporting and MIS tends to be a poor cousin in application design and only done as an afterthought. Abusing denormalised data. Overdoing denormalised data and trying to maintain it within the application is a recipe for data integrity issues. Use denormalisation sparingly. Not wanting to add a join to a query is not an excuse for denormalising. Scared of writing SQL. SQL isn't rocket science and is actually quite good at doing its job. O/R mapping layers are quite good at doing the 95% of queries that are simple and fit well into that model. Sometimes SQL is the best way to do the job. Dogmatic 'No Stored Procedures' policies. Regardless of whether you believe stored procedures are evil, this sort of dogmatic attitude has no place on a software project. Not understanding database design. Normalisation is your friend and it's not rocket science. Joining and cardinality are fairly simple concepts - if you're involved in database application development there's really no excuse for not understanding them.

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

有一件事我想补充,学习使用分析函数,如分区BY, RANK, DENSE_RANK (Oracle)。它们对于复杂的查询是绝对必要的。

其他建议是,如果可能的话,在您的开发团队中有一个专门的数据库开发人员,他应该是SQL、数据库建模、调优等方面的专家(但不是DBA)。这种技能是一笔巨大的财富。

根据我的经验: 不与有经验的dba沟通。