• 1. a candidate key: 候选
• 2. Selecting a Key Abstraction Candidate: 选择一个候选的重要的抽象

• 1.No non-prime attribute in the table is functionally dependent on a part (proper subset) of a candidate key.
  不存在非主属性对任一候选键滴部分函数依赖。
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• 2.Those new pieces include two new nuclei (byproducts), some photons (gamma rays), but also some more free neutrons, which is the key that makes nuclear fission a good candidate to generate energy.
  产生的新组成包括两个新原子核(副产物)、一些光子(伽马射线)以及更多的自由中子，它们是参与核裂变反应并产生能量的关键。
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• 3.For example, if you are creating a Customer table and the CustomerID is marked as not null, then when you define the primary key, CustomerID will show as a candidate column.
  例如，如果您要创建一个 Customer 表并且 CustomerID 被标记为 not null，则当您定义主键时，CustomerID 将会显示为备选列。
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