Quiz Discussion

Which of the following is correct

• 1]

  a SQL query automatically eliminates duplicates

• 2]

  SQL permits attribute names to be repeated in the same relation

• 3]

  a SQL query will not work if there are no indexes on the relations

• 4]

  None of these

Which of the following is a comparison operator in SQL?

• 1]

  =

• 2]

  LIKE

• 3]

  BETWEEN

• 4]

  All of the above

Which of the following is an advantage of view?

• 1]

  Data security

• 2]

  Derived columns

• 3]

  Hiding of complex queries

• 4]

  All of the above

To delete a particular column in a relation the command used is

• 1]

  UPDATE

• 2]

  DROP

• 3]

  ALTER

• 4]

  DELETE

What is an advantage of placing computations in SQL views

• 1]

  To save users from having to write an expression

• 2]

  To ensure that the results are consistent

• 3]

  To accomplish both of the above

• 4]

  None of the above

Which of the following is a legal expression in SQL?

• 1]

  SELECT NULL FROM EMPLOYEE;

   

• 2]

  SELECT NAME FROM EMPLOYEE;

   

• 3]

  SELECT NAME FROM EMPLOYEE WHERE SALARY = NULL;

   

• 4]

  None of the above

   

The SQL ALTER statement can be used to

• 1]

  Change the table structure

• 2]

  Change the table data

• 3]

  Add rows to the table

• 4]

  Delete rows from the table

What is not an advantage of stored procedures?

• 1]

  Greater security

• 2]

  SQL can be optimized

• 3]

  Code sharing

• 4]

  Increased network traffic

Which one of the following is not true for a view

• 1]

  View is derived from other tables

• 2]

  View is a virtual table

• 3]

  A view definition is permanently stored as part of the database

• 4]

  View never contains derived columns

Count function in SQL returns the number of

• 1]

  Values

• 2]

  Distinct values

• 3]

  Groups

• 4]

  Columns