天津大学试卷专用纸
学院计算机科学与技术专业计算机科学与技术 班 年级 学号 姓名 共 7 页 第 1 页
2011～2012 学年第 1 学期期末考试试卷
《数据库原理》（ A 卷 共 7 页）
（考试时间：2012 年 1 月 6 日）
题号
一
二
三
四
五
六
成绩
核分人签字
得分
一、选择题（20 分）
1. What does the abbreviation DBMS stand for in the database technology? ( A )
A. Database Management System B. Data Manipulation System
C. Database and Media System D. Data Base Manager System
2. Which one of the following data models was proposed by Codd in his 1970's paper?
( C )
A. hierarchical data model B. network data model
C. relational data model D. object-oriented data model
3. What one of the following options is not a part of a data model? ( B )
A. structure of data B. storage of data
C. operations on the data D. constraints on the data
4. Assume that three relations R(A, B), S(A, B) and T(A, B) have the same schema.
Which one of the following relational algebra equations does not hold? ( D )
A.
()R S R R S
B.
R
..R A S B
S
..
()
R A S B
RS
C.
(R
)S
T
R
(S
)T
D.
( ) ( )
AA
R S S T
5. Given the following two schemas
Movies (title, year, length, genre, studioName, producerC#)
MovieExec (name, address, cert#, netWorth)
Which of the following relational algebra expressions can express the constraints “the
producerC# of each Movies tuple must also appear in the cert# of some MovieExec
tuple” ( A )
A.
##
( ) ( )
producerC cert
Movies MovieExec
B.
##
( ) ( )
cert producerC
MovieExec Movies
C.
##
( ) ( )
producerC cert
Movies MovieExec
D.
##
( ) ( )
cert producerC
MovieExec Movies
6. Given a relation R(A, B, C), the functional dependency AB→C holds on R. If
(a
1
, b
1
, c
1
), (a
2
, b
2
, c
2
), (a
1
, b
1
, c
3
), (a
1
, b
2
, c
4
) are four tuples of R and we know
a
1
a
2
and b
1
b
2
, then which one of the following equations must hold? ( B )
A. c
1
= c
2
B. c
1
= c
3
C. c
1
= c
4
D. c
2
=c
4
7. Consider a relation R(A
1
, A
2
, A
3
) has the only key {A
1
, A
2
}. Which of the following
statements is right? ( D )
A. {A
1
} is also a key. B. {A
2
} is also a key.
C. {A
1
, A
3
} is a superkey. D. {A
1
, A
2
, A
3
} is a superkey.
8. Consider the following E/R diagram. Which is the correct relation converted from the
relationship SC? ( C )
Students SC Courses
sno sname cno cname
grade
A. SC (sno, grade) B. SC (cno, grade)
C. SC (sno, cno, grade) D. SC (sno, cno)
9. In the undo-logging rules, if transaction T modifies database elements X, then the log
record of the form <T, X, v> must be written to disk ( A )
A. before the new value of X is written to disk.
B. after the new value of X is written to disk.
C. after the <COMMIT T> log record is written to disk.
D. None of the above is correct.
10. Suppose T
1
and T
2
are two transactions, and A is a database element. Which of the
following statements about database locking is not correct? ( D )
A. If T
1
has already held an exclusive lock on A, then T
2
cannot obtain a shared lock on A.
B. If T
1
has already held a shared lock on A, then T
2
can obtain a shared lock on A.
C. If T
1
has already held an exclusive lock on A, then T
2
cannot obtain an exclusive lock on A.
D. If T
1
has already held a shared lock on A, then T
2
can obtain an exclusive lock on A.
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