武汉理工大学数据库系统原理总复习题完整版含答案Word文档格式.docx

1、 we can now define information as:Knowledge derived from data.Data presented in a meaningful context.Data processed by summing, ordering, averaging, grouping, comparing or other similar operations.1.10 What problem can occur when a database is processed by more than one user? When more than one user

2、 employs a database application, these is always the chance that one users work may interfere with others.1.12 What is the purpose of the largest databases at e-commerce companies such as Amazon.? The largest databases are those that track customer browser behavior.（用来记录用户的浏览行为的。）1.13 How do the e-c

3、ommerce companies use these databases? . E-commerce companies use Web activity databases to determine which items on a Web page are popular and successful and which are not.1.14 How do digital dashboard and data mining applications differ from transaction processing applications? Digital dashboards

4、and other reporting systems assess past and current performance. Data mining applications predict future performance.1.15 Explain why a small database is not necessarily simpler than a large one.What are the functions of application programs? Supposed we have 2 company which are different in sales b

5、ut have similar database. Though the difference in sale, both have the same kinds of data, about the same number of tables of data, and the same level of complexity in data relationships. Only the amount of data varies from one to the other. Thus, although a database for a small business may be smal

6、l, it is not necessarily simple.1.18 What is Structured Query Language （SQL）, and why is it important? Structured Query Language （SQL） is an internationally recognized standard language. Because it can be understood by all commercial DBMS products, in database processing and the fact that database a

7、pplications typically send SQL statements to the DBMS for processing.1.19 What does DBMS stand for? The database management system.1.20 What are the functions of the DBMS? It can be used to create, process, and administer the database.1.21 Name three vendors of DBMS products. IBM, Microsoft, Oracle.

8、1.22 Define the term database. A database is a self-describing collection of integrated tables.1.23 Why is a database considered to be self-describing? ANSWER: A database is self-describing because it contains a description of itself. Thus, databases contain not only tables of user data, but also ta

9、bles of data that describe that user data.1.24 What is metadata? How does this term pertain to a database? databases contain not only tables of user data, but also tables of data that describe that user data. Such descriptive data is called metadata because it is data about data.1.25 What advantage

10、is there in storing metadata in tables? Because metadata is stored in tables, you can use SQL to query it. Thus, by learning how to write SQL to query user tables, you will also learn how to write SQL to query metadata.1.26 List the components of a database other than user tables and metadata. Table

11、s of user data Metadata Indexes Stored procedures Triggers Security data Backup/recovery data1.27 Is Microsoft Access a DBMS? Why or why not? No, Microsoft Access is not just a DBMS. Rather, it is a personal database system: a DBMS plus an application generator.Because although Microsoft Access cont

12、ains a DBMS engine that creates, processes, and administers the database, it also contains form, report, and query components that are the Microsoft Access application generator1.37 List several consequences of a poorly designed database. -They may require application developers to write overly comp

13、lex and contrived SQL to get wanted data.-they may be difficult to adapt to new and changing requirements.-they may fail in some other way.1.38 Explain two ways that a database can be designed from existing data.The first type of database design involves databases that are constructed from existing

14、Data.A second way that databases are designed is for the development of new information systems.1.39 What is a data warehouse? What is a data mart? The data warehouse and data mart databases store data specifically organized for research and reporting purposes, and these data often are exported to o

15、ther analytical tools, such as SASs Enterprise Miner, IBMs SPSS Data Modeler, or TIBCOs Spot fire Metrics. 1.40 Describe the general process of designing a database for a new information system. First, the team creates a data model from the requirements statements and then transforms that data model

16、 into a database design.1.41 Explain two ways that databases can be redesigned. In the first, a database is adapted to new or changing requirements. This process sometimes is called database migration. In the migration process, tables may be created, modified, or removed; relationships may be altere

17、d; data constraints may be changed; and so forth. The second type of database redesign involves the integration of two or more databases. This type of redesign is common when adapting or removing legacy systems. It is also common for enterprise application integration, when two or more previously se

18、parate information systems are adapted to work with each other. 1.42 What does the term database migration mean? The process of a database is adapted to new or changing requirements.1.43 Summarize the various ways that you might work with database technology. In our career, we may work with database

19、 technology as either a user or as a database administrator. As a user, you may be a knowledge worker who prepares reports, mines data, and does other types of data analysis or you may be a programmer who writes applications that process the database. Alternatively, you might be a database administr

20、ator who designs, constructs, and manages the database itself. Users are primarily concerned with constructing SQL statements to get and put the data they want. Database administrators are primarily concerned with the management of the database.1.44 What job functions does a knowledge worker perform

21、? preparing reports, mining data, and doing other types of data analysis.1.45 What job functions does a database administrator perform? designing, constructing, and managing the database itself.1.47 What need drove the development of the first database technology? The need for data integration drove

22、 the development of the first database technology.1.48 What are Data Language/I and CODASYL DBTG?Data Language/I （DL/I） used hierarchies or trees （see Appendix G） to represent relationships.This subcommittee developed a standard data model that came to bear its namethe CODASYL DBTG model. It was an

23、unnecessarily complicated model. This data relationship used data structures called networks.1.49 Who was E. F. Codd? E.F.Codd was a little-known IBM engineer published a paper in the Communications of the ACM3 in which he applied the concepts of a branch of mathematics called relational algebra to

24、the problem of “shared data banks,” as databases were then known. The results of this work are now the relational model for databases, and all relational database DBMS products are built on this model. 1.50 What were the early objections to the relational model?1.51 Name two early relational DBMS pr

25、oducts. Oracle Database, DB2.1.52 What are some of the reasons for the success of Oracle Database?1, it would run on just about any computer and just about any operating system.2, Oracle Database had, and continues to have, an elegant and efficient internal design.1.53 Name three early personal comp

26、uter DBMS products. dBase, R:base, Paradox.1.55 What was the purpose of OODBMS products? State two reasons that OODBMS products were not successful. They were designed to make it easy to store the data encapsulated in OOP objects.There were two reasons for their lack of acceptance. First, using an O

27、ODBMS required that the relational data be converted from relational format to object-oriented format. By the time OODBMS emerged, billions upon billions of bytes of data were stored in relational format in organizational databases. No company was willing to undergo the expensive travail of converti

28、ng those databases to be able to use the new OODBMS. Second, object-oriented databases had no substantial advantage over relational databases for most commercial database processing. As you will see in the next chapter, SQL is not object oriented. But it works, and thousands of developers have creat

29、ed programs that use it. Without a demonstrable advantage over relational databases, no organization was willing to take on the task of converting their data to OODBMS format. 1.56 What characteristic of HTTP was a problem for database processing applications? HTTP is a stateless protocol; a server

30、receives a request from a user, processes the request, and then forgets about the user and the request. Many database interactions are multistage. A customer views products, adds one or more to a shopping cart, views more products, adds more to the shopping cart, and eventually checks out. A stateless protocol cannot be used for such applications. 1.57 What is an open source DBMS product? Which of the five DBMS products th