问题
单项选择题
在数据库系统设计的需求分析阶段，除了要产生系统的数据字典和确定系统边界外，还应该产生系统的______。
A．数据流图
B．数据流程图
C．数据ER图
D．数据视图
答案
参考答案：A
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在数据库系统设计的需求分析阶段，除了要产生系统的数据字典和确定系统边界外，还应该产生系统的______。
A．数据流图
B．数据流程图
C．数据ER图
D．数据视图
参考答案：A
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| My father enjoys bike riding.Ever since I was little, I've always loved going biking with my dad. __1__, as I became a teenager, other thins began to draw my__2__.Suddenly, it was important to do things with__3__.I saw my dad every evening at home.Why did I have to__4__my Sundays to allday bike trips with him, too?If my indifference (冷漠) hurt him, my father kept__5__, but he would always let me know when he was planning a bike trip__6__I wanted to come. It was a Sunday morning, and I was in low__7__.Two of my friends had gone to the movies without inviting me.Just then my father__8__my room." It's a beautiful day.Want to go for a__9__, today, Beck?""Leave me alone!"I impatiently__10__. Those were the last words I said to him before he left the house that__11__. Several hours later, the police called us, __12__us that Dad had a traffic accident.My father's injuries were serious.It took several days before he could__13__speak.Beside his bed I eldhishandgently__14__of hurting him. "Daddy...I'm sorry...""It's okay, sweetheart.I'll be okay." "No, " I said, "I__15__what I said to you that day.You know, that morning?" "Sweetheart, I don't__16__anything about that day.I remember kissing you goodnight the night before, though." He__17__a weak smile. I felt regretful for my thoughtless remark, for I__18__, wanted him to leave me alone.My teacher once told me that__19__have immeasurable power.They can hurt or they can heal.And we all have the __20__to choose our words.I intend to do that very carefully from now on. | ||||
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