如何识别关系模式的最高范式?
假设我们有一个关系模式。我们如何表述该关系的最高常态?
例如:
- Art_Object(Art_Id、标题、描述、国家/地区、艺术家、时代、年份)
Let's say we have a relation schema. How can we state the highest normal of that relation?
For example:
- Art_Object (Art_Id, Title, Description, Country, Artist, Epoch, Year)
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“我想知道 Art_Object 是什么范式?这是我学校的测试。”
任何给定设计的正常形式取决于所具有的函数依赖性。
如果没有给出那组函数依赖关系,这个问题根本无法回答。
如果唯一保存的FD是Art_ID-> {所有属性},那么您的设计属于 5NF。
相反,如果有一些额外的FD,例如艺术家->国家,那么这个设计甚至不是3NF。
"i wanna know What normal form Art_Object is in? this is the test from my school."
Normal form of any given design depends on which functional dependencies hold.
Without being given that set of functional dependencies, the question is simply unanswerable.
If the only FD that holds is Art_ID -> {all attributes}, then your design is in 5NF.
If on the contrary there were some additional FD like Artist -> Country, then this design isn't even 3NF.