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16.  Which of the following clauses can be used to generate summary reports in a database?
              a.  ORDER BY             b. REPORT BY           c. GROUP BY            d. SUMMARY
        B.  State whether the following statements are True or False:
          1.  UNIQUE and PRIMARY KEY constraints are same.                                             __________
           2.  Attributes cannot be added to an existing table in a database.                          __________
           3.  Using UPDATE-SET command, we can perform conditional updates in a table in MySQL.       __________

           4.  An underscore(_) character along with LIKE operator represents exactly one occurrence of an
              arbitrary character.                                                                     __________
           5.  A name of a column defined using AS clause in a SELECT statement is known as an alias.   __________
           6.  A primary key attribute can have a NULL value.                                          __________
        C.  Fill in the blanks.
           1.  The SELECT statement, combined with __________ clause, retrieves the records from a MySQL table and displays them
              without any repetition.
           2.  An attribute in a relation is a foreign key if it is a __________ key in some other table.
           3.  A __________ restricts the values an attribute can take.

           4.  __________ constraint ensures that no two rows have the same value in the specified columns.
           5.  __________ clause is used with the SELECT statement to specify conditions on groups of data to be displayed.
           6.  In case of a nested query, the __________ query may use the result of an __________ query.
           7.  Along with the SELECT statement, the __________ clause is used to display the result of an SQL query in ascending or
              descending order with respect to specified attribute values.
        D.  Answer the following questions:
           1.  Which of the following statements are true?
              (i)   Names of the columns in a table must be unique.
              (ii)  Tuples in a table do not appear in a specific order.
              (iii)  No component of the primary key can repeat in different tuples in a table.
              (iv)  DBA decides which tables should be included in the database.
              (v)  Any tuple can be deleted from any table without affecting the consistency of the database.
              (vi)  Delete operation changes the database state.
              (vii)  A failed insert operation does not change the database state.
              (viii) End-users have no role in the design of the database.
              (ix)  An end-user decides which components of the database he/she will access.
              (x)  DBMS may allow a user to access the EMPLOYEE table to a user, but may not allow access to the data relating to
                  employees SALARY>100000.
              (xi)  DBMS may allow a user to access the salary of the employees in the EMPLOYEE table, but may not allow access to
                  the Address of the employees.
           2.  Consider a table that stores the data of an item using the following attributes:
              ItemCode, ItemName, Price
              Suggest an appropriate domain for each attribute.
           3.  Can a relation have two identical tuples? Why / Why not?
           4.  Define the following with respect to databases:
              (i)   Domain
              (ii)  Constraint
              (iv)  Candidate Key
              (v)  Alternate Key


          278  Touchpad Informatics Practices-XI
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