平凡的多值依赖与非平凡的多值依赖: 若X→→Y,而Z为空集,则称X→→Y为平凡的多值依赖;若Z不为空,则称其为非平凡的多值依赖。 转载https://www.2cto.com/database/201404/290140.html
《数据库系统概念》(Database System Concepts):这本由Abraham Silberschatz、Henry F. Korth和S. Sudarshan合著的经典教材是数据库系统的权威参考书之一。它详细介绍了规范化理论和实践,包括BCNF的概念和应用。 《数据库设计与规范化》(Database Design and Normalization):这本由Adrienne Watt和Nelson Eng合著的书重点...
BCNF范式 https://www.2cto.com/database/201404/290140.html BCNF是3NF的改进形式 一个满足BCNF的关系模式的条件: 1.所有非主属性对每一个码都是完全函数依赖。 2.所有的主属性对每一个不包含它的码,也是完全函数依赖。 3.没有任何属性完全函数依赖于非码的任何一组属性。
一次Lab的作业题目如下: A luxury car-rental company has been tracking their rental data in a simple spreadsheet, but now wants to migrate to a proper database. Consider the table given below, containing some sample data. (a) Identify at least 10 functional dependencies (non-trivial with minima...
3) Design an academic genealogy database with one entity set: Academics. Consider academics with doctoral degrees only. The information to record about academics includes their name, discipline, year of graduation, institution, dissertation title, dissertation chair, dissertation committee members (assume...
Seminar task from college subject SQL Practicum. App that finds primary key candidates and handles database normalization - decomposition to Third Normal Form and Boyce-Codd normal form. 🔑 bcnfprimary-key3nfdecomposition-algorithmcandidate-key ...
https://www.2cto.com/database/201404/290140.html BCNF是3NF的改进形式 一个满足BCNF的关系模式的条件: 1.所有非主属性对每一个码都是完全函数依赖。 2.所有的主属性对每一个不包含它的码,也是完全函数依赖。 3.没有任何属性完全函数依赖于非码的任何一组属性。
While I do understand what the normal forms are, I have trouble working with them. I am following a course in database systems and somehow I am a bit lost on this. I have tried Google, stackoverflow, slides of the course and the book, but examples seem to throw me off track every ...
换言之,BCNF关系FDs中左侧必须都是键。 References [1] R. Ramakrishnan and J. Gehrke,Database management systems. Boston: Mcgraw-Hill, 2011.
AnIntroductiontoDatabaseSystem6.2.1函数依赖6.2.2码6.2.3范式6.2.4第二范式(2NF)6.2.5第三范式(3NF)6.2.6BC范式(BCNF)*6.2.7多值依赖*6.2.8第四范式(4NF)6.2.9规范化小结AnIntroductiontoDatabaseSystem例:关系模式STJ(S,T,J)中,S表示学生,T表示教师,J表示课程语义:假设每一教师只教一门课T→J每门...