数据库试题 英文卷

哈尔滨理工大学2007－ 2008学年 第一学期考试试题 A 卷 软件学院软件工程系 出题教师： 刘欢 系主任：考试科目： 数据库系统 考试时间：120分钟 试卷总分100分 考试班级： 题号 I II III IV V 总分 得分 评卷教师 I ． Blank-filling questions in DBS situation.（2 marks × 15 = 30 marks ） 1、To illustrate the concept of a data model, we outline two data models in this section : the __entity-relationship _______________ model and the _______relational. ______ model. 2、Since many database-systems users are not computer trained, developers hide the complexity from users through several levels of abstraction, to simplify users‟ interactions with the system:__physical level______ level, __logical level_____ level and view level. 3、A database-management system is a collection of interrelated ____data _____ and a set of __programs______ to access those data. 4、Data model is a collection of conceptual tools for describing __data,_______, ____data relationships,_______________, ____data semantics________________, and consistency constraints. 5、A ___view_____ is a virtual relation which is made visible to a user in. 6、A ___file_____ is organized logically as a sequence of records. 7、There are four different types of database-system users ：_______________, _________________, sophisticated users and specialized users.8、A _____________ is a unit of program execution that accesses and possibly updates various data items.9、A data _________ is a file that stores metadata about the structure of the database.1、entity-relationship , relational. (无先后顺序)2、physical level, logical level. (无先后顺序)3、data , programs.4、data, data relationships, data semantics. (无先后顺序)装订线软件专业 班级：学号： 姓名：5、view6、file7、naïve users, application programmers. (无先后顺序)8、transaction9、data dictionaryII ． Briefly-answer questions. ( 5 marks × 4 = 20 marks)1、Here is an authorization graph.a) List the users who still have authorization after only edge m is moved. b) List the users who still have authorization after only edge l is moved.2、Please list the five duties of a database administrator.3、Please give the definition of “trigger ” in database system.4、Explain the distinctions among the terms superkey, candidate key and primary key.III ． C omplete the following queries using relational algebra expressions.( 4 marks × 3 = 12 marks)Consider the relational database of a banking enterprise with the following relation schemas, where the primary keys are underlined. branch (branch_name, branch_city, assets) customer (customer_name, customer_street, customer_city) loan (loan_number, branch_name, amount) borrower (customer_name, loan_number) account (account_number, branch_name, balance) depositor (customer_name, account_number)1、Find the names of all customers who have a loan, an account, or both, from the bank.2、Delete all account records in the Perryridge branch.U 1U 5U 3 U 2DBA l mU 4哈尔滨理工大学2007－2008学年第一学期考试试题A卷3、Insert information in the database specifying that Smith has $1200 in account A-973 at the Perryridge branch.IV．Answer the following questions and queries in SQL. ( 4 marks ×5 = 20marks)From the database schema above, give an expression in SQL for each of queries 2, 3, 4 and 5.1.Define the relation …account‟ in SQL.Tip: Describe primary keys, foreign keys and check constrains if necessary. 2.To find all loan number for loans made at the Perryridge branch with loanamounts greater than $1200.3.Find all customers who have both a loan and an account4.Find the names of all branches where the average account balance is morethan $1,200.5.Find all loan number which appear in the loan relation with null values foramountV．Resolve the following questions of designing. (18marks)A university registrar‟s office maintains data about the following entities:(a)students, including student-id, name, program;.(b)instructors, including id, name, department and title.(c)courses, including c-number, title, credits, syllabus and prerequisites;(d)course offerings, including course number, year, semester, section number,instructor(s), timings, and classroom;Further, the enrollment of students in courses and grades awarded to students in each course the are enrolled for must be appropriately modeled. A class meets only at one particular place and time.1.Construct an E-R diagram for the university registrar‟s office. ( 10 marks)(This E-R diagram needn‟t model a class meeting at different places atdifferent times; also needn‟t guarantee that the database does not have twoclasses meeting at the same place and time.)2.Design a relational database corresponding to the preceding E-R diagramwith marked primary keys. ( 8 marks)。