题型:问答题 简答题 —Don't play near the classroom, please.—_____ [ ]A. Yes, I do B. Sorry, I won'tC. No. I don't D. Not at all 查看答案
题型:问答题 简答题 设关系模式R < U,F >,其中U = { A,B,C,D,E },F = {A→BC,C→D,BC→E,E→A },则分解ρ= {R1(ABCE),R2(CD) }满足 (43) 。A.具有无损连接性、保持函数依赖B.不具有无损连接性、保持函数依赖C.具有无损连接性、不保持函数依赖D.不具有无损连接性、不保持函数依赖 查看答案