同济大学数据库课程考核试卷-A卷-秋季数据库期中考试-英语-参考答案1
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同济大学课程考核试卷（A 卷）
2012 — 2013 学年第一学期
课号：10014501 课名：数据库系统原理（双语） 考试考查：考试
此卷选为：期中考试( )、期终考试( )、重考( ) 试卷
年级 专业 学号 姓名 得分
Ⅰ. Multiple choice (20 marks, 2 marks each)
（C ）1. Five basic relational algebra operations are , others can be derived
from these operations.
A. ，，，， B. ，，，，
C. ，，，， D. ，，，，
（ABD）2. The following aggregation function(s) will neglect null value.
A. SUM B. MAX
C. COUNT D. AVG
（A. ）3. Given R<U, F>, U={A,B,C}, F={BC}, a decomposition of R is ={AB,
BC}, and the decomposition is:
A. lossless-join, dependency preserving B. lossless-join, not dependency preserving
C. lossy-join, dependency preserving D. lossy-join, not dependency preserving
（BD ）4. When we generate relational schemas from an E-R diagram, the rules for
relationship sets are:
A. for a binary 1: n relationship set, translate it into a relation, and the primary key
of the relationship set is the primary key of the “1” side entity set;
B. for a binary 1: n relationship set, translate it into a relation, and the primary key
of the relationship set is the primary key of the “n” side entity set;
C. a binary 1: n relationship set can be united with the “1” side entity set, and
translated into one relation;
D. a binary 1: n relationship set can be united with the “n” side entity set, and
translated into one relation;
（ABC）5. If RBCNF, then:
A. non-attributes are entirely functional dependent on non-key attributes;
B. all key attributes are entirely functional dependent on each candidate key that
does not contain them;
C. all partial dependencies and transitive dependencies are removed for any
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