Final Review

Find all the candidate keys

  1. 分出
    • L
    • R
    • LR
  2. 依次遍历
    • L
    • L+LR

Decompose the schema in BCNF

Is Loss-less join Decompositon

Is Dependency Preservation

Find canonical cover of the functional dependencies

  • 函数右部依赖分解为单属性
  • 消除冗余属性
  • 消除冗余的函数依赖

Decompose the schema in 3NF

  • Fm
  • 合并左部相同
  • 每个FD构成新的R
  • 在构成的R中如果每个R都不存在 R 的候选键，那么把 R 的候选键作为一个模式放入模式集
Table Of Contents
Final Review
Find all the candidate keys
Decompose the schema in BCNF
Is Loss-less join Decompositon
Is Dependency Preservation
Find canonical cover of the functional dependencies
Decompose the schema in 3NF