最简洁的：Difference between 3NF and BCNF is that for a functional dependency A->B, 3NF allows this dependency in a relation if B is a *** attribute and A is not a candidate key 稍长点的：consider that:It should be noted that most relations that are in 3NF are also in ...
用一个例子理解1NF,2NF,3NF,BCNF。。(此篇纯水,无价值) 设计一个论坛的数据库: (1) 用户:用户名,email,主页,电话,联系地址 (2) 帖子:发帖标题,发帖内容,回复标题,回复内容 第一次:将数据库设计为仅存在表。 create table1(用户名 email 主页 电话 联系地址 发帖标题 发帖内容 回复标题 回复内容) 很显然...
What does relocate() mean in boost multi-index container? I have read the manual from boost documentations, but I want to see a simple example and see the difference of using and not using the relocat... How can I implement nested boost::mpl::fold ...
【简答题】INF消除___依赖,即规范化为2NF;2NF消除依赖非主属性对码的传递函数,即规范化为3NF。 查看完整题目与答案 【简答题】学生的学习是一种规范化的学习。 () 查看完整题目与答案 【判断题】医药经营企业建立完备的文件系统,不但可以避免因口头传达引起的失误,而且能使管理走上程序化、规范化。 A. ...
The basic difference between 3NF and BCNF is that 3NF eliminates the transitive dependency from a relation and a table to be in BCNF, for each functional dependency X->Y, X must be the super key.