理工大学数据库系统原理总复习题（完整版含答案）
1. Questions
1.1What is the purpose of a database?
ANSWER：The purpose of a database is to help people track of things.
1.2What is the most commonly used type of database?
ANSWER: the most commonly used type of database is the relational database.
1.7 Define the terms data and information. Explain how the two terms differ.
ANSWER: Data are recorded facts and numbers.
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 W hat problem can occur when a database is processed by more than one user?
ANSWER: When more than one user employs a database application, these is always the chance that one user's work may interfere with other's.
1.12 What is the purpose of the largest databases at e-commerce companies such as Amazon.?
ANSWER: 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-commerce companies use these databases? .
ANSWER: 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?
ANSWER: Digital dashboards 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?
ANSWER: Supposed we have 2 company which are different in sales but 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 small, it is not necessarily simple.
1.18 What is Structured Query Language (SQL), and why is it important?
ANSWER: 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 applications typically send SQL statements to the DBMS for processing.
1.19 What does DBMS stand for?
ANSWER: The database management system.
1.20 What are the functions of the DBMS?
ANSWER: It can be used to create, process, and administer the database.
1.21 Name three vendors of DBMS products.
ANSWER: IBM, Microsoft, Oracle.
1.22 Define the term database.
ANSWER: 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 tables of data
that describe that user data.
1.24 What is metadata? How does this term pertain to a database?
ANSWER: 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 is there in storing metadata in tables?
ANSWER: 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. ?Tables of user data
?Metadata
?Indexes
?Stored procedures
?Triggers
?Security data
?Backup/recovery data
1.27 Is Microsoft Access a DBMS? Why or why not?
ANSWER: 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 contains a DBMS engine that creates, processes, and administers the database, it also contains form, report, and query components that are the Microsoft Access application generator
1.37 List several consequences of a poorly designed database.
ANSWER:
-They may require application developers to write overly complex 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.
ANSWER:
The first type of database design involves databases that are constructed from existing 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?
ANSWER: The data warehouse and data mart databases store data specifically organized for research and reporting purposes, and these data often are exported to other analytical tools, such as SAS’s Enterprise Miner, IBM's SPSS Data Modeler, or TIBCO's Spot fire Metrics.
1.40 Describe the general process of designing a database for a new information system.
ANSWER: First, the team creates a data model from the requirements statements and then transforms that data model into a database design.
1.41 Explain two ways that databases can be redesigned.
ANSWER:
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 altered; 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 separate information systems are adapted to work with each other.
1.42 What does the term database migration mean?
ANSWER: 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.
ANSWER: In our career, we may work with database 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 administrator 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?
ANSWER: preparing reports, mining data, and doing other types of data analysis.
1.45 What job functions does a database administrator perform?
ANSWER: designing, constructing, and managing the database itself.
1.47 What need drove the development of the first database technology?
ANSWER: The need for data integration drove the development of the first database technology.