期末试题-数据库技术与应用.doc

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1、 班级： 学号： 姓名：北京邮电大学20072008学年第一学期数据库技术与应用期末考试试题考试注意事项一、学生参加考试须带学生证或学院证明，未带者不准进入考场。学生必须按照监考教师指定座位就坐。二、书本、参考资料、书包等与考试无关的东西一律放到考场指定位置。三、学生不得另行携带、使用稿纸，要遵守北京邮电大学考场规则，有考场违纪或作弊行为者，按相应规定严肃处理。四、学生必须将答题内容做在专用答题纸上，做在试卷、草稿纸上一律无效。考试课程数据库技术与应用考试时间 年 月 日题号一二三四五六七八总分满分2030103010得分阅卷教师True-False Questions（20）题号123456

2、78910答案题号11121314151617181920答案Multiple Choice Questions（30）题号12345678910答案题号11121314151617181920答案题号21222324252627282930答案Fill in the Blank Questions（10）题号答案12345678910Essay Questions（30）12345Give your suggestion about this course（10）True-False Questions（1point*20）1. The purpose of a database is to

3、 help people keep track of things.2. The relational model was first proposed in 1970 by E. F. Codd at IBM.3. A relation is a three-dimensional table.4. An asterisk (*) following the SELECT verb means that all columns are to be obtained.5. The SQL keyword GROUP BY instructs the DBMS to group together

4、 those rows that have the same value in a column.6. In an E-R model, the three types of maximum cardinality are 1:1, 1:N and N:M.7. A null value is an attribute value that has been set to zero.8. A data constraint is a limitation on data values.9. In a relational database design, all relationships a

5、re expressed by creating a foreign key.10. A transaction is a group of alternative database actions from which the database can choose to perform only one of them.11. Two-phased locking has a growing phase and a shrinking phase.12. Repeatable Reads isolation is the most restrictive level of isolatio

6、n.13. A database save is used to mark the end of a transaction.14. To add a NULL column to a table, we simply use the MODIFY TABLE statement.15. Deleting tables and relationships is basically a matter of dropping foreign key constraints and then dropping the tables.16. The SQL keyword DELETE is used

7、 to delete a tables structure.17. Joins that show only matching rows from the joined tables in their results are called inner joins.18. An SQL virtual table is called a view.19. SQL triggers are used for providing default values, validity checking, updating views, and performing referential integrit

8、y actions.20. Stored procedures have the advantage of greater security, decreased network traffic, SQL optimized by the DBMS compiler, and code sharing.Multiple Choice Questions（1 point*30）1. A database stores:a.)data.b.)relationships.c.)metadata.d.)a and be.)a, b and c2. A program whose job is to c

9、reate, process and administer databases is called the _.a.)Database Modeling Systemb.)Database Management Systemc.)Data Business Model Systemd.)Relational Model Managere.)Data Business Management Service3. A database is considered self-describing because _ .a.)all the users data is in one placeb.)it

10、 reduces data duplicationc.)it contains a description of its own structured.)it contains a listing of all the programs that use ite.)All of the above.4. A very popular development technique used by database professionals for database design is known as _ .a.)data martsb.)normalizationc.)data modelsd

11、.)entity-relationship data modelinge.)data migration5. In an SQL query, which SQL keyword is used to state the condition that specifies which rows are to be selected?a.)EXISTSb.)FROMc.)SELECTd.)SETe.)WHERE6. In an SQL query, which of the following symbols is used by ANSI SQL to represent a single un

12、specified character?a.) (underscore)b.)? (question mark)c.)* (asterisk)d.)% (percent)e.)# (pound)7. Given a table with the structure: EMPLOYEE (EmpNo, Name, Salary, HireDate), which of the following would find all employees whose name begins with the letter S using standard SQL?a.)SELECT *FROM EMPLO

13、YEEWHERE Name IN S;b.)SELECT EmpNoFROM EMPLOYEEWHERE Name LIKE S;c.)SELECT *FROM NameWHERE EMPLOYEE LIKE S*;d.)SELECT *FROM EMPLOYEEWHERE Name LIKE S%;e.)None of the above.8. Given a table with the structure: EMPLOYEE (EmpNo, Name, Salary, HireDate), which of the following is not a valid ANSI SQL co

14、mmand?a.)SELECT *FROM EMPLOYEEWHERE Name LIKE Ja%;b.)SELECT COUNT(*)FROM EMPLOYEEWHERE Salary 30000;c.)SELECT COUNT(EmpNo)FROM EMPLOYEE;d.)SELECT HireDate, COUNT(*)FROM EMPLOYEEWHERE Salary 30000;e.)SELECT HireDate, COUNT(*)FROM EMPLOYEEGROUP BY HireDate;9. A relation _ .a.)has rows containing data

15、about an entityb.)has columns containing data about attributes of the entityc.)has cells that hold only a single valued.)has no two identical rowse.)All of the above.10. Which of the following is true about the functional dependency A (X, Y)?a.)X is functionally dependent on A.b.)A determines Y.c.)A

16、 is a determinant.d.)X and Y are functionally dependent on A.e.)All of the above.11. A relation is in fourth normal form if it is in BCNF and it has no _ .a.)transitive dependenciesb.)multivalued dependenciesc.)partial dependenciesd.)deletion dependenciese.)referential integrity conflicts12. The adv

17、antages of normalization include _ .a.)the elimination of modification anomaliesb.)the elimination of duplicated datac.)more complex SQL for multitable subqueries and joinsd.)a and be.)a, b and c13. To check for null values in a column in a table, use the SQL phrase _ .a.)ISb.)IS NOTc.)IS NULLd.)COU

18、NT(IS NOT)e.)COUNT(IS NULL)14. A composite attribute is an attribute that _ .a.)is multivaluedb.)describes a characteristic of the relationshipc.)consists of a group of attributes d.)is calculated at run-timee.)is an identifier15. Maximum cardinality refers to _ .a.)the most instances of one entity

19、class that can be involved in a relationship instance with another entity classb.)the minimum number of entity classes involved in a relationshipc.)whether or not an instance of one entity class is required to be related to an instance of another entity classd.)whether or not an entity is a weak ent

20、itye.) None of the above.16. An entity whose existence depends on the presence of another entity, but whose identifier does not include the identifier of the other entity is a(n) _ .a.) strong entityb.)weak entityc.)ID-dependent entityd.)a and ce.)b and c 17. You are given an E-R diagram with two en

21、tities, ORDER and CUSTOMER, as shown below, and are asked to draw the relationship between them. If a given customer can place only one order and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities?ORDERC

22、USTOMERa.)0:1b.)1:1c.)1:Nd.)N:1 e.)N:M18. When an entity has a relationship to itself, we have a (n) _ .a.) supertype/subtype relationshipb.)archetype/instance relationshipc.)recursive relationshipd.)a or ce.)b or c 19. Each attribute of an entity becomes a _ of a table.a.)columnb.)primary keyc.)for

23、eign keyd.)alternate keye.)b or d20. Which of the following is not true about surrogate keys?a.)They are identifiers that are supplied by the system, not the users.b.)They have no meaning to the users.c.)They are nonunique within a table.d.)They can be problematic when combining databases.e.)The DBM

24、S will not allow their values to be changed.21. To which of the following actions are referential integrity constraints not applied?a.)createb.)insertc.)modifyd.)deletee.)referential integrity constraints are applied to all of the listed actions22. Which SQL keyword is used to impose restrictions on

25、 a table, data or relationship?a.)SETb.)CREATEc.)SELECTd.)ALTERe.)CONSTRAINT23. SQL views are constructed from .a.)CREATE statementsb.)INSERT statementsc.)UPDATE statementsd.)SELECT statementse.)VIEW statements24. In the SQL statementsSELECT C1.CustName, C1.SalesRepNoFROM CUSTOMER C1;the C1 is calle

26、d a(n) _ .a.)termb.)aliasc.)conventiond.)phrasee.)label25. If a DEFAULT constraint is included when a new column is added to a table, the default value is applied to .a.)all existing rows at the time the column is addedb.)all new rowsc.)all new rows but only after the UPDATE command is issuedd.)a an

27、d be.)a and c26. When dropping tables and relationships, which of the following steps are included in the process the order of the steps listed below is not relevant, only the steps themselves?a.)Drop the foreign key constraints from the tablesb.)Drop the tablesc.)Drop the primary key constraints fr

28、om the tablesd.)a and be.)a, b and c27. Which of the following is not a database administration responsibility of a DBA?a.)Managing the database structureb.)Managing data activityc.)Managing the DBMSd.)Maintaining the data repositorye.)All of the above are database administration responsibilities of

29、 a DBA.28. Measures that are taken to prevent one users work from inappropriately influencing another users work are called:a.)concurrency control.b.)checkpoint.c.)database recovery.d.)database logging.e.)interleaving.29. The situation that occurs when two users are each waiting for a resource that

30、the other person has locked is known as a(n):a.)lost update problem.b.)deadlock.c.)inconsistent read problem.d.)inconsistent write problem.e.)checkpoint.30. Locks that are placed assuming that a conflict will not occur are called:a.)dynamic.b.)explicit.c.)implicit.d.)optimistic.e.)pessimistic.Fill i

31、n the Blank Questions（1 point*10）1. SQL stands for .2. To remove duplicate rows from the result of a query, specify the SQL qualifier .3. If a table is a relation then it is in NF.4. To limit the number of rows retrieved from a table, use the SQL keyword .5. By default, the identifier of the entity

32、becomes the of the corresponding table.6. Rows in a table can be changed by using the statement.7. To add a NULL column to a table, we use the TABLE statement.8. A(n) is a series of actions to be taken on the database such that either all of them are performed successfully or none of them is perform

33、ed at all.9. A(n) lock locks the item from access of any type.10. A(n) cursor processes a snapshot of the relation that was taken when the cursor was opened.Essay Questions（6 points*5）1. Briefly describe subqueries and joins. Explain when each is not an acceptable alternative for the other.2. Briefl

34、y describe the process of converting an extended E-R model into a relational database design.3. The following database will be used in this question:GENERAL SALES DATABASE:SALESREPSalesRepNoRepNameHireDate654Jones01/02/1999734Smith02/03/2000345Chen01/25/1998434Johnson11/23/1998CUSTOMERCustNoCustName

35、BalanceSalesRepNo9870Winston5003458590Gonzales3504347840Harris8006544870Miles100345Explain the use of the SQL statement CREATE TABLE. Do NOT discuss the ALTER statement in your answer, but DO include an example based on the SALESREP table in the General Sales database.4. Explain the concept of serializable transactions.5. Explain the SQL Server IDENTITY constraint.Give your suggestion about this course（10 points*1）