了解每种范式是否重要 [英] Is it Important to Understand Each Normal Form

问题描述

我已经研究数据库设计和编程已有相当长的时间了，但是我仍然无法理解每个范式(1NF，2NF，3NF).

I have been studying database design and programming for quite some time now, but I still can't get a grasp of understanding each individual normal form (1NF, 2NF, 3NF.)

就像数据在任何时候都处于第三范式一样，它已经自动处于第二范式和第一范式中，通过从一开始就对数据进行完全归一化，整个过程实际上就可以不太麻烦地完成了.我可以通过安排数据来轻松完成此操作，以便每个表中的列(除了主键之外)仅依赖于整个主键.

Seeing as anytime the data is in Third Normal Form, it is already automatically in Second and First Normal Form, can the whole process actually be accomplished less tediously by fully normalizing the data from the start. I can accomplish this easily by arranging the data so that the columns in each table, other than the primary key, are dependent only on the whole primary key.

如果我们可以按照我所描述的那样简单地将数据少一点乏味地完全标准化，那么理解每种个体范式的重要性有多大?

How important is it to understand each individual normal form if we can simply fully normalize the data less tediously by doing what I have described?

我最终要问的是:在对数据进行归一化时，经过每个范式的步骤是否重要，还是因为结果最终相同而只是转到第三范式"是否合适?/p>

What I'm ultimately asking is: Is it important to go through the steps of each normal form when normalizing data, or is it appropriate to just go to Third Normal Form seeing as the result is ultimately the same?

推荐答案

我强烈建议您了解每种范式，因为这将帮助您确定或调查当前数据库可能存在的任何问题，因为有时您可能没有一个完美的方案时间和理解每种范式都会帮助您了解现有数据库设计中的当前问题(如果有的话).

I highly recommend understanding each normal form as this will help you determine or investigate any issues with a current database may have as sometimes you might not have the perfect scenario each time and understanding each normal form will help you to understand the current problems with an existing database design if there are any.

逐步介绍不同的常规形式将帮助您弄清楚我们为什么这样做，这是为了实现E. F. Codd指定的目标.规范化的目标说明如下:1.释放关系的集合，使其摆脱不希望的插入，更新和删除依赖关系.2.在引入新类型的数据时，减少了重组关系集合的需求，从而延长了应用程序的寿命.3.使关系模型对用户更具参考价值.4.为了使关系的收集对查询统计数据保持中立，这些统计数据会随着时间的流逝而发生变化.

Going through step by step through the different normal forms will help you to figure out why we do this and this is to achieve the goals specified by E. F. Codd. The objectives of normalization were stated as follows: 1. To free the collection of relations from undesirable insertion, update and deletion dependencies. 2. To reduce the need for restructuring the collection of relations as new types of data are introduced, and thus increase the life span of application programs. 3. To make the relational model more informative to users. 4. To make the collection of relations neutral to the query statistics, where these statistics are liable to change as time goes by.

这里有一张图像，可以帮助您更好地理解不同的正常形式.P.S.BCNF实际上是3.5NF而不是4NF

Here is a image to help you understand the different normal forms better. P.S. BCNF is actually 3.5NF not 4NF

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