A. ) ( CustomerID,ProviderID,BuyDate ) → GoodsName
B.) (CustomerID,ProviderID,BuyDate) → GoodsName,ProviderID
C. ) ( CustomerID,ProviderID,BuyDate ) → GoodsClassID
D. ) ( CustomerID,ProviderID,BuyDate ) → ProviderID
[单选题]下列不属于非平凡函数依赖的是______。A.) (CustomerID,ProviderID,BuyDate)→GoodsNameB.) (CustomerID,ProviderID,BuyDate)→GoodsName,ProviderIDC.) (CustomerID,ProviderID,BuyDare)→GoodsClassIDD.) (CustomerID,ProvideIID,BuyDate)→ProviderIDA.B.C.D.
[单选题]下列不属于非平凡函数依赖的是______。A.(CustomerID,ProviderID,BuyDate)→GoodsNameB.(CustomerID,ProviderID,BuyDate)→GoodsName,ProviderIDC.(CustomerID,ProviderID,BuyDate)→GoodsClassIDD.(CustomerID,ProviderID,BuyDate)→ProviderID
[单选题]下列不属于非平凡函数依赖的是______。A.(CustomerID, ProviderID, BuyDate)→Good-sNameB.(CustomerID, ProviderID, BuyDate)→Good-sName, ProviderIDC.(CustomerID, ProviderID, BuyDate)→Good-sClassIDD.(CustomerID, ProviderID, BuyDate)→ProviderID
[单选题]下列约束中能确保一个函数依赖是完全非平凡函数依赖的是______。A.仅当其右边的属性集是左边属性集的子集______。B.仅当其右边属性集中的属性都不属于左边的属性集C.仅当其右边属性集中至少有一个属性不属于左边的属性集D.仅当其右边属性集中的属性都属于左边的属性集
[单选题]下列函数依赖中______是平凡的FD。A.AB->BCB.AB->CDC.AB->AD.AB->D
[单选题]下列函数依赖中( )是平凡的FD。A.AB→BCB.AB→CDC.AB→AD.AB→D
[单选题]下列约束中能确保一个函数依赖是完全非平凡函数依赖的是______。A.) 仅当其右边的属性集是左边属性集的子集B.) 仅当其右边属性集中的属性都不属于左边的属性集C.) 仅当其右边属性集中至少有一个属性不属于左边的属性集D.) 仅当其右边属性集中的属性都属于左边的属性集A.B.C.D.
[多选题]下面哪几个依赖是平凡函数依赖()。A.(Sno,Cname,Grade)→(Cname,Crade)B.(Sno,Cname)→(Cname,Grad