题型:问答题 简答题 Again and again the doctor ______the crying girl, but he couldn’t find what was wrong with her.A.looked overB.looked after C.looked forD.looked out 查看答案
题型:问答题 简答题 设关系模式R<U,F>,其中U=H,I,J,K,L,若F=H→IJ,J→K,IJK→L,L→H,L→K,则F的最小函数依赖集Fmin=______,关系模式R的候选关键字是______。A.{H}、{L}和{IJ} B.{H)、{K)和{L} C.{K}、{L}和{IJ} D.{H}、{K}、{L}和{IJ} 查看答案