潜龙勿用.txt

SQL语句初级

 (d) control the order in which a query’s rows are sorted  

 Correct answer is  (c)  

 Your score on this question is: 10.00  

 Feedback: 
   
See section 2.1.2, subsection "Aliasing in SQL: The AS operator," in the course notes.
 
 

--------------------------------------------------------------------------------

 4. 
 When removing a table from the schema, using the RESTRICT option would  
 

  (a) remove the table and all other tables that the specified table refers to
 (b) remove the table and all references to it
 (c) recursively remove the table and all other tables that the removed table refers to
 (d) remove the table if there are no references to it  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 5. 
 In SQL, a database can be destroyed by which of the following?  
 

  (a) the command DELETE DATABASE
 (b) the command DESTROY DATABASE
 (c) the command DROP SCHEMA
 (d) a series of DESTROY TABLE commands  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 6. 
 In SQL, when destroying a database, the RESTRICT option removes  
 

  (a) the data but not the schema
 (b) the data and schema from the specified database, but not from related databases
 (c) everything in the specified database: the data, schema, etc.
 (d) the schema if the database has no data (empty tables)  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 7. 
 In SQL, which of the following clauses can be used to sort results in ascending or descending order of attribute values?  
 

  (a) ARRANGE BY
 (b) GROUP BY
 (c) ORDER BY
 (d) SORT  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 8. 
 In a FROM clause of a SELECT statement in SQL, a table can be aliased with which of the following operators?  
 

  (a) AS
 (b) @
 (c) ALIAS
 (d) RENAME  

 Correct answer is  (a)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 9. 
 When specifying a selection criterion in SQL, attributes can be renamed with which of the following operators?  
 

  (a) AS
 (b) RENAME
 (c) ALIAS
 (d) @  

 Correct answer is  (a)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 10. 
 In SQL, which of the following operators can be used to express searches that test for a range in a selection condition?  
 

  (a) START and END
 (b) FROM and TO
 (c) RANGE
 (d) BETWEEN  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 Go to top of assessment.  

 Total score: 90.00 

 ? Copyright 2004 iCarnegie, Inc. All rights reserved.  

View Assessment Result


   

 Family Name:  Huang  
 Given Name:  Chun  
 Login:  nwpu043869  
 E-mail: [e-mail]  
 Status:  Enrolled  

 Assessment Name: Multiple-Choice Quiz 2  
 Instance:  1   

 Section: NWPU-SSD7-10  
 During:  Spring 2007  
 Section Status:  Active  

 For course:  Database Systems  
  (SSD7)  

 Corresponding to:  SSD7  
 At:  Software College of Northwestern Polytechnical University  
 

--------------------------------------------------------------------------------
 

 Your performance was as follows: 

 You took 13 minutes on this assessment from Fri Apr 27 22:56:01 UTC+0800 2007 to Fri Apr 27 23:08:34 UTC+0800 2007. 

 Total score: 90.00 
 
 

 

 1. 
 What information is necessary when specifying the structure of a table?  
 

  (a) the name of the table and the amount of storage space to be allocated to the table
 (b) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes
 (c) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have
 (d) the name of the table and the names of the table's attributes  

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 



--------------------------------------------------------------------------------

 2. 
 The foreign key in a table T1 _____ the same _____ as the corresponding primary key in table T2. 
must have, name 
need not have, name 
must have, domain 
 
 

  (a) I, II, and III
 (b) I and III
 (c) II and III
 (d) I and II  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 3. 
 The degree of a table is the number of _____ in the table.  
 

  (a) keys
 (b) rows
 (c) columns
 (d) foreign keys  

 Correct answer is  (c)  

 Your score on this question is: 0.00  
 

--------------------------------------------------------------------------------

 4. 
 The cardinality of a table is the number of _____ in the table.  
 

  (a) keys
 (b) foreign keys
 (c) columns
 (d) rows  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 5. 
 The SQL clause to perform a set difference operation is  
 

  (a) OMIT
 (b) REJECT
 (c) EXCEPT
 (d) DIFFER  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 6. 
 Which of the following SQL statements can be used to remove a row from a table?  
 

  (a) DESTROY
 (b) DELETE
 (c) ERASE
 (d) REMOVE  

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 7. 
 DDL is used to  
 

  (a) define the structure of database applications.
 (b) add contents to tables.
 (c) access the contents of tables.
 (d) specify the structure of a database.  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 8. 
 For two tables to be union compatible, the tables should be the same with respect to which of the following?  
 

  (a) cardinality
 (b) degree
 (c) name
 (d) keys  

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 9. 
 DML is used to  
 

  (a) add/modify/delete data in the database.
 (b) manipulate the structure of database applications.
 (c) add and delete tables.
 (d) specify the structure of a database.  

 Correct answer is  (a)  

 Your score on this question is: 10.00  
 

--------------------------------------------------------------------------------

 10. 
 The term query by example refers to  
 

  (a) example SQL queries provided by the DBMS that users can modify to suit their current needs
 (b) example SQL queries provided by other users that can be modified to suit current needs
 (c) a query for SQL examples
 (d) a visual query language developed by IBM  

 Correct answer is  (d)  

 Your score on this question is: 10.00  

 Feedback: 
   
See section 1.2.3 in the course notes.
 
 

--------------------------------------------------------------------------------

 Go to top of assessment.  

 Total score: 90.00 

 ? Copyright 2004 iCarnegie, Inc. All rights reserved.  
View Assessment Result


   

 Family Name:  Huang  
 Given Name:  Chun  
 Login:  nwpu043869  
 E-mail: [e-mail]  
 Status:  Enrolled  

 Assessment Name: Multiple-Choice Quiz 1  
 Instance:  1   

 Section: NWPU-SSD7-10  
 During:  Spring 2007  
 Section Status:  Active  

 For course:  Database Systems  
  (SSD7)  

 Corresponding to:  SSD7  
 At:  Software College of Northwestern Polytechnical University  
 

--------------------------------------------------------------------------------
 

 Your performance was as follows: 

 You took 9 minutes on this assessment from Fri Apr 27 22:37:17 UTC+0800 2007 to Fri Apr 27 22:46:06 UTC+0800 2007. 

 Total score: 42.86 
 
 

 

 1. 
 An E-Commerce system consists of the following components. Which of the same components must be included in a database management system? 
The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 
A collection of programs must be included that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains, such as in a library information system. 
A collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. 
 
 

  (a) I only
 (b) II only
 (c) I, II, and III
 (d) II and III only  

 Correct answer is  (b)  

 Your score on this question is: 0.00  

 Feedback: 
   A DBMS refers to just the set of general-purpose programs to control data.  
 



--------------------------------------------------------------------------------

 2. 
 An E-Commerce system consists of the following components. Which of these same components will constitute a database system? 
The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 
A collection of programs that control the data, such as programs to create, maintain, and manipulate the data constitutes a database system. These programs can be easily used to create, maintain, and manipulate data in other domains such as in a library information system. 
A collection of programs that operate on the data, but are specific to the E-commerce system, constitutes a database system. These programs enable users to browse through the store-items, place orders, track shipping, etc. 
 
 

  (a) I, II, and III
 (b) I only
 (c) II only
 (d) I and II only  

 Correct answer is  (a)  

 Your score on this question is: 14.29  

 Feedback: 
   A database system includes the data, the DBMS, and the application-specific programs that operate on that data.  
 

--------------------------------------------------------------------------------

 3. 
 In a database system, whose responsibility is it to provide data consistency?  
 

  (a) the DBMS's
 (b) the user's
 (c) the application programmer's
 (d) the database administrator's  

 Correct answer is  (a)  

 Your score on this question is: 14.29  
 

--------------------------------------------------------------------------------

 4. 
 An E-Commerce database contains data about customers, products, orders, system response times, etc. Which of the following can be specified as integrity constraints in an E-Commerce database system? 
No two products can have the same product ID. 
The DBMS response time for all Web requests should be at most 2 seconds. 
A customer order cannot have more than one shipping address. 
 
 

  (a) I only
 (b) I, II, and III
 (c) I and II only
 (d) I and III only  

 Correct answer is  (d)  

 Your score on this question is: 0.00  

 Feedback: 
   The constraints I, II and III specify the application semantics of the data captured in the E-Commerce database. Constraint III, although it seems contrary to common sense, is not something that can be prohibited by the DBMS because the DBMS is general purpose. The response time of the DBMS cannot be enforced by the DBMS. It depends on factors such the processor speed, memory available, etc.  
 

--------------------------------------------------------------------------------

 5. 
 An E-Commerce system consists of the following components. Which of these same components must be included in a database? 
The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 
A database must include a collection of programs that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains. 
A database must include a collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. 
 
 

  (a) I, II, and III
 (b) II only
 (c) I and II only
 (d) I only  

 Correct answer is  (d)  

 Your score on this question is: 0.00  

 Feedback: 
   Database refers to just the data  
 

--------------------------------------------------------------------------------

 6. 
 A database is needed for which of the following application scenarios? 
A video store that needs to keep track of data about members, about videos carried by the store, about videos rented by members, as well as data concerning borrow-date, return-date, and payment information. 
In the human resources department of a company, information about employees, their titles, their salaries and sick days, and about vacation days taken by each employee. 
A computer-simulated video game which needs to calculate and display, the physical (x, y) location of each actor in the game, the speed with which they are moving at the current instant, the direction in which they are moving, the action they are performing, the angle at which the game-player is viewing the scene. 
 
 

  (a) I only
 (b) I and II only
 (c) I, II, and III
 (d) I and III only  

 Correct answer is  (b)  

 Your score on this question is: 0.00  

 Feedback: 
   (c) Unrelated data such as site downtimes, price of goods, employees, etc do not constitute a database.  
 

--------------------------------------------------------------------------------

 7. 
 The physical storage structure will be _____ to the application programmer in a database approach, and will be _____ to the application programmer in a file system approach.  
 

  (a) hidden, visible
 (b) visible, visible
 (c) hidden, hidden
 (d) visible, hidden  

 Correct answer is  (a)  

 Your score on this question is: 14.29  

 Feedback: 
   The layer of abstraction offered by a DBMS hides the physical storage structure from the application programmer.  
 

--------------------------------------------------------------------------------

 Go to top of assessment.  

 Total score: 42.86 

 ? Copyright 2004 iCarnegie, Inc. All rights reserved.