潜龙勿用2.txt

ssd7练习选择题5-9的答案

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 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) visible, hidden
 (d) hidden, 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.  
 

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 Go to top of assessment.  

 Total score: 71.43 

 ? Copyright 2004 iCarnegie, Inc. All rights reserved.  

 Your performance was as follows: 

 You took 4 minutes on this assessment from Sat Apr 28 08:52:22 UTC+0800 2007 to Sat Apr 28 08:55:45 UTC+0800 2007. 

 Total score: 90.00 
 
 

 

 1. 
 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) II and III
 (c) I and II
 (d) I and III  

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 



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 2. 
 What information is necessary when specifying the structure of a table?  
 

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

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

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

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

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 

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

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

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 

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 5. 
 For two tables to be union compatible, the tables should be the same with respect to which of the following?  
 

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

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

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 6. 
 Which of the following SQL statements can be used to create a relational table?  
 

  (a) APPEND
 (b) INSERT
 (c) ADD
 (d) CREATE  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

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 7. 
 DML is used to  
 

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

 Correct answer is  (b)  

 Your score on this question is: 0.00  
 

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 8. 
 The SQL clause to perform a set UNION operation is  
 

  (a) UNITE
 (b) MELD
 (c) COMBINE
 (d) UNION  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

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 9. 
 A difference operation can be applied to tables that  
 

  (a) have the same column names
 (b) have the same name
 (c) are union compatible
 (d) are the same size  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

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 10. 
 The term query by example refers to  
 

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

 Correct answer is  (b)  

 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 Your performance was as follows: 

 You took 5 minutes on this assessment from Sat Apr 28 08:47:44 UTC+0800 2007 to Sat Apr 28 08:52:10 UTC+0800 2007. 

 Total score: 100.00 
 
 

 

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

  (a) the name of the table and the names of the table's attributes
 (b) the name of the table and the amount of storage space to be allocated to the table
 (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, the names of the table's attributes, the data types of attributes, and the formats of attributes  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 



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 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 II
 (c) I and III
 (d) II and III  

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

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

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

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

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 

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

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

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

 Correct answer is  (a)  

 Your score on this question is: 10.00  
 

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 5. 
 A difference operation can be applied to tables that  
 

  (a) are the same size
 (b) are union compatible
 (c) have the same column names
 (d) have the same name  

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 

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 6. 
 The SQL clause to perform a set UNION operation is  
 

  (a) COMBINE
 (b) MELD
 (c) UNION
 (d) UNITE  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

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 7. 
 Which of the following SQL statements can be used to add a row to a table?  
 

  (a) APPEND
 (b) ADD
 (c) INSERT
 (d) CREATE  

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

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 8. 
 Which of the following SQL statements can be used to remove a row from a table?  
 

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

 Correct answer is  (c)  

 Your score on this question is: 10.00  
 

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 9. 
 What can be specified in the selection condition of a SELECT statement?  
 

  (a) a Boolean operation
 (b) the time at which the selection should be performed
 (c) the conditions under which the statement should be executed
 (d) an arithmetic operation  

 Correct answer is  (a)  

 Your score on this question is: 10.00  
 

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 10. 
 The term query by example refers to  
 

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

 Correct answer is  (a)  

 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: 100.00 

 ? Copyright 2004 iCarnegie, Inc. All rights reserved.  

Your performance was as follows: 

 You took 43183 minutes on this assessment from Thu Mar 29 09:03:16 UTC+0800 2007 to Sat Apr 28 08:45:45 UTC+0800 2007. 

 Total score: 90.00 
 
 

 

 1. 
 The degree of a table is the number of _____ in the table.  
 

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

 Correct answer is  (d)  

 Your score on this question is: 10.00  
 



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

 2. 
 What information is necessary when specifying the structure of a table?  
 

  (a) the name of the table and the names of the table's attributes
 (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 and the amount of storage space to be allocated to the table
 (d) 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  

 Correct answer is  (b)  

 Your score on this question is: 10.00  
 

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

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

 Correct answer is  (a)  

 Your score on this question is: 10.00  
 

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

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