功能依赖性和规范化 [英] Functional dependency and normalization
问题描述
我正在尝试寻找大量资源来研究功能依赖性和规范化。
I am trying to find a great resource to study for functional dependency and normalization.
任何人都知道我应该去哪里？我很难区分FD是1NF，2NF还是3NF？
Anyone have any idea where should I look to? I am having difficulty differentiating whether a FD is in 1NF, 2NF or 3NF?
我一直在阅读Wikipedia，并使用Google搜索来寻找良好的研究成果，但找不到任何能用简单的术语解释的研究。
I've been reading Wikipedia and used Google search to find good research, but can't find any that explains it in simple terms.
也许大家都可以分享一生中学习FD和归一化的方式。
Maybe you all can share on how you learned FD's and normalization during your life as well.
推荐答案
功能依赖项定义属性之间的功能关系。例如： PersonId 从功能上确定 BirthDate （通常写为 PersonId-> BirthDate ）。另一种说法是：一个人的任何给定实例都有一个出生日期。请注意，相反可能正确也可能不正确。许多人可能在同一天出生。给定出生日期，我们可能会发现许多 PersonId 共享该日期。
A functional dependency defines a functional relationship between attributes. For example: PersonId functionally determines BirthDate (normally written as PersonId -> BirthDate). Another way of saying this is: There is exactly one Birth Date for any given instance of a person. Note that the converse may or may not be true. Many people may have been born on the same day. Given a BirthDate we may find many PersonId sharing that date.
功能依赖项集可用于合成关系（表）。
的前3个范式的定义（包括Boyce Codd范式（BCNF））以
的形式表示给定的一组关系如何表示功能依赖性。第四和第五范式涉及多值依赖关系（又是一锅鱼）。
Sets of functional dependencies may be used to synthesize relations (tables). The definition of the first 3 normal forms, including Boyce Codd Normal Form (BCNF) is stated in terms of how a given set of relations represent functional dependencies. Fourth and fifth normal forms involve Multi-Valued dependencies (another kettle of fish).
这里有一些关于功能依赖项，规范化和数据库设计的免费资源。
在学习此材料时，请准备锻炼您的大脑和数学技能。
Here are a few free resources about Functional Dependencies, Normalization and database design. Be prepared to exercise your brain and math skills when studying this material.
以下是来自各个学术网站的幻灯片放映 ...
The following are "slide shows" from various academic sites...
- Functional Dependencies
- Functional Dependencies and Normalization for Relational Databases
- The Relational Data Model: Functional-Dependency Theory
以下为学术文章文件。阅读更多但值得付出努力。
The following are academic papers. Heavier reading but well worth the effort.
- 功能依赖理论在关系数据库中的应用
- 关系数据库中五种形式的简单指南
- < a href = http://www.almaden.ibm.com/cs/people/fagin/tods92.pdf rel = nofollow noreferrer>在关系数据库中保证较高范式的简单条件
- The Application of Functional Dependency Theory to Relational Databases
- A Simple Guide to Five Normal Forms in Relational Database
- Simple Conditions for Guaranteeing Higher Normal Forms in Relational Databases
如果您对此主题非常感兴趣，建议您拿出现金，购买一本有关关系数据库设计的好书
。例如： CJ Date对数据库系统的介绍
If you are seriously interested in this subject I suggest you put out the cash for a good book on the subject of Relational Database Design. For example: An Introduction to Database Systems by C.J. Date
这篇关于功能依赖性和规范化的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
