PLSQL Mid Term Exam Semester 2

1. Which of the following statements about packages is NOT true ?
All procedures and functions must be declared in the specification. (*)
Cursors can be declared in the specification.
The body contains the detailed code of the subprograms.
Variables can be declared in the body.
The specification must be created before the body.

2. The following package specification has been created:
CREATE OR REPLACE PACKAGE mypack IS
FUNCTION myfunc(p_funcparam DATE) RETURN BOOLEAN;
PROCEDURE myproc(p_procparam IN NUMBER);
END mypack;
Which of the following will correctly invoke the package subprograms? (Choose two.) (Choose all correct answers)
mypack.myfunc('22-JAN-07');
mypack.myproc(35);(*)
IF NOT mypack.myfunc(SYSDATE) THEN DBMS_OUTPUT.PUT_LINE('Message');
END IF; (*)
myproc(40);
v_num := mypack.myproc(22);

3. Which one of the following can NOT be part of a Package ?
Procedures
Explicit cursors
Triggers (*)
Functions
Global variables

4. What is wrong with the following syntax for creating a package specification?
CREATE OR REPLACE PACKAGE mypack IS

 g_constant1 NUMBER(6) := 100;
FUNCTION func1 (p_param1 IN VARCHAR2);
FUNCTION func2;
END mypack;

You cannot declare constants in the specification.
A package must contain at least one procedure.
The RETURN datatype of the functions must be specified.(*)
The first line should be: CREATE OR REPLACE PACKAGE SPECIFICATION mypack IS
Nothing is wrong, this code contains no errors.

5. Which of the following statements about a package initialization block is true?
It cannot contain any SQL statements.
It is an anonymous block at the end of a package body. (*)
It is a procedure in a package that must be invoked before the rest of the package can be used.
It is an anonymous block in the package specification.
It is executed automatically every time any global variable in the package is referenced.

6. Package HRPACK contains the following public function:
FUNCTION empfunc (p_deptno NUMBER) RETURN NUMBER IS
BEGIN
UPDATE employees SET salary = salary * 1.1
WHERE department_id = p_deptno;
RETURN SQL%ROWCOUNT;
END empfunc;
What will happen when the following SQL statement is executed?
SELECT department_name, hrpack.empfunc(department_id)
FROM departments;

The SELECT will fail because you cannot return SQL%ROWCOUNT from a packaged function.
The SELECT will fail because you cannot call packaged functions from within a SQL statement.
The SELECT will fail because you cannot execute a DML statement from within a query.
The SELECT will succeed because it is referencing a different table from the function. (*)

7. Package TAXPACK declares a global variable G_TAXRATE NUMBER(2,2) . The value of the tax rate is stored in table TAXTAB in the database. You want to read this value automatically into G_TAXRATE each time a user session makes its first call to TAXPACK. How would you do this?


Declare the global variable as:
g_taxrate NUMBER(2,2) := SELECT tax_rate FROM taxtab;

Create a database trigger that includes the following code:
SELECT tax_rate INTO taxpack.g_taxrate FROM taxtab;

Add a private function to the package body of TAXPACK, and invoke the
function from the user session.

Add a package initialization block to the package body of TAXPACK. (*)

8. We never need to use a forward declaration when invoking a public subprogram. True or False?
True (*)
False

9. We need to declare a package variable named MYVAR, which can be referenced by any subprogram in the package but can NOT be referenced from outside the package. In the following code, where should MYVAR be declared?
CREATE OR REPLACE PACKAGE varpack IS
-- Point A
...
END varpack;
CREATE OR REPLACE PACKAGE BODY varpack IS
-- Point B
PROCEDURE varproc IS
-- Point C
BEGIN
...
END varproc;
PROCEDURE ...
...
-- Point D
END varpack;

Point A
Point B (*)
Point C
Point D
Point B or Point C, they will both work

10. In a package, public components are declared in the specification but private components are not. True or False?
True (*)
False

11. We want to remove the specification (but not the body) of package BIGPACK from the database. Which of the following commands will do this ?
DROP PACKAGE bigpack;
DROP PACKAGE SPECIFICATION bigpack;
DROP PACKAGE bigpack SPECIFICATION;
DROP PACKAGE HEADER bigpack;
None of the above (*)

12. Which of the following will display the detailed code of the subprograms in package DEPTPACK in your schema ?
SELECT text FROM USER_SOURCE
WHERE name = 'DEPTPACK'
AND type = 'PACKAGE'
ORDER BY line;


 SELECT text FROM USER_SOURCE
WHERE name = 'DEPTPACK'
AND type = 'PACKAGE BODY'
ORDER BY line; (*)

 SELECT text FROM USER_SOURCE
WHERE object_name = 'DEPTPACK'
AND object_type = 'PACKAGE BODY'
ORDER BY line;

SELECT text FROM USER_SOURCE
WHERE name = 'DEPTPACK'
AND type = 'BODY'
ORDER BY line;

13. Package OLDPACK is in your schema. What will happen when the following statement is executed?
DROP PACKAGE oldpack;

The body will be dropped but the specification will be retained.
The specification will be dropped but the body will be retained.
Both the specification and the body will be dropped. (*)
The statement will fail because you must drop the body before you can drop the specification.

14. Examine the following package specification:
CREATE OR REPLACE PACKAGE taxpack IS
CURSOR empcurs IS SELECT * FROM employees;
PROCEDURE taxproc;
END mypack;
The package body of TAXPACK also includes a function called TAXFUNC.
Which one of the following statements is NOT true?

The procedure can be invoked by:
BEGIN
taxpack.taxproc;
END;

The package will not compile because you cannot declare a cursor in the specification. (*)

 TAXPROC is a public procedure and TAXFUNC is a private function

TAXPROC can invoke TAXFUNC if TAXPROC is coded before TAXFUNC

TAXPROC can open the cursor

15. Package NEWPACK contains several procedures and functions, inc
luding private function PRIVFUNC. From where can PRIVFUNC be invoked? (Choose two.)
(Choose all correct answers)
From an anonymous block
From any procedure in NEWPACK (*)
From any private function in another package
From any function in NEWPACK (*)
From any public procedure in another package

16. The DBMS_OUTPUT.PUT procedure places text in a buffer but does not display the contents of the buffer. True or False?
True (*)
False

17. Which of the following best describes the purpose of the UTL_FILE package?
It is used to load binary files such as employees' photos into the database.
It is used to read and write text files stored outside the database. (*)
It is used to find out how much free space is left on an operating system disk.
It is used to query CHAR and VARCHAR2 columns in tables.

18. Why is it better to use DBMS_OUTPUT only in anonymous blocks, not inside stored subprograms such as procedures?
Because DBMS_OUTPUT cannot be used inside procedures
Because anonymous blocks display messages while the block is executing, while procedures do not display anything until their execution has finished
Because DBMS_OUTPUT should be used only for testing and debugging PL/SQL code (*)
Because DBMS_OUTPUT can raise a NO_DATA_FOUND exception if used inside a packaged procedure

19. The UTL_FILE package can be used to create binary files such as JPEG s as well as text files. True or False?
True
False (*)

20. You want to create a function which drops a table. You write the following code:
CREATE OR REPLACE FUNCTION droptab
(p_tab_name IN VARCHAR2)
RETURN BOOLEAN IS
BEGIN
DROP TABLE p_tab_name;
RETURN TRUE;
EXCEPTION
WHEN OTHERS THEN RETURN FALSE;
END;
Why will this procedure not compile successfully?

Because you can never drop a table from inside a function
Because the PL/SQL compiler cannot check if the argument of p_tab_name is a valid table-name (*)
Because you do not have the privilege needed to drop a table
Because you cannot use RETURN in the exception section

21. MARY wants HENRY to be able to query her EMPLOYEES table. Mary executes the following code:
DECLARE
v_grant_stmt VARCHAR2(50);
BEGIN
v_grant_stmt := 'GRANT SELECT ON employees TO henry';
DBMS_SQL.EXECUTE(v_grant_stmt);
END;
Mary has successfully granted the privilege to Henry. True or False?
True
False (*)

22. Examine the following code:
CREATE OR REPLACE PROCEDURE myproc IS
CURSOR c_curs IS SELECT view_name FROM user_views;
BEGIN
FOR v_curs_rec IN c_curs LOOP
EXECUTE IMMEDIATE 'DROP VIEW ' || v_curs_rec.view_name;
END LOOP;
END;
What will happen when this procedure is invoked?

All views in the user's schema will be dropped. (*)
The procedure will not compile successfully because the syntax of EXECUTE IMMEDIATE is incorrect.
The procedure will raise an exception because Dynamic SQL can drop tables but cannot drop views.
The procedure will raise an exception because one of the views is a complex view.

23. The easiest way to include DDL statements in a PL/SQL block is touse the DBMS_SQL package. True or False?
True
False (*)

24. Package MULTIPACK declares the following global variable:
g_myvar NUMBER;
User DICK executes the following:
multipack.g_myvar := 45;
User HAZEL now connects to the database. Both users immediately execute:
BEGIN
DBMS_OUTPUT.PUT_LINE(multipack.g_myvar);
END;
What values will Dick and Hazel see?

Dick: 45, Hazel: 45
Dick: 45, Hazel: 0
Dick: 45, Hazel: null (*)
Dick: 0, Hazel: 0
Both queries will fail because the syntax of DBMS_OUTPUT.PUT_LINE is incorrect

25. When a user session changes the value of a package variable, the new  value can immediately be seen by other sessions. True or False?
True
False (*)

26. In the following code:
CREATE TRIGGER mytrigg
INSTEAD OF INSERT OR UPDATE ON my_object_name
FOR EACH ROW
BEGIN ...
my_object_name can be the name of a table. True or False?
True
False (*)

27. INSTEAD OF triggers are always row triggers, even if FOR EACH RO
W is omitted. True or False?
True (*)
False

28. Which of the following can NOT be coded in the body of a DML trig
ger? (Choose two.) (Choose all correct answers)
IF DELETING THEN
IF SELECTING THEN (*)
IF INSERTING THEN
IF UPDATING ('JOB_ID') THEN
IF OTHERS THEN (*)

29. With which kind of trigger can the :OLD and :NEW qualifiers be used?
DDL triggers
Database Event triggers
Statement triggers
Row triggers (*)
AFTER triggers

30. MARY and JOE's schemas each contain an EMPLOYEES table. JOE creates the following trigger:
CREATE TRIGGER upd_trigg
AFTER DELETE ON joe.employees
FOR EACH ROW
BEGIN
DELETE FROM mary.employees
WHERE employee_id = :OLD.employee_id;
END;
A third user TOM needs to delete rows from JOE's EMPLOYEES table. What object privileges will TOM and JOE need?

TOM does not need any object privileges, but JOE needs DELETE on both TOM.EMPLOYEES and MARY.EMPLOYEES

TOM needs DELETE on JOE.EMPLOYEES and JOE needs DELETE on MARY.EMPLOYEES (*)
JOE does not need any object privileges, but TOM needs DELETE on MARY.EMPLOYEES
TOM needs DELETE on MARY.EMPLOYEES and JOE needs EXECUTE on TOM.UPD_TRIGG

31. You need to disable all triggers that are associated with DML statements on the DEPARTMENTS table. Which of the following commands should you use?
ALTER TABLE departments DISABLE ALL TRIGGERS; (*)
ALTER TRIGGER DISABLE ALL ON departments;
ALTER TABLE departments DISABLE TRIGGERS;
DISABLE ALL TRIGGERS ON departments;
ALTER TABLE departments DROP ALL TRIGGERS;

32. User AYSEGUL successfully creates the following trigger:
CREATE TRIGGER loc_trigg
BEFORE UPDATE ON aysegul.locations
BEGIN ....
AYSEGUL now tries to drop the LOCATIONS table. What happens?

An error message is displayed because you cannot drop a table that is associated with a trigger.
The table is dropped and the trigger is disabled.
The trigger is dropped but the table is not dropped.
Both the table and the trigger are dropped. (*)
None of the above.

33. The database administrator wants to write a log record every time an Oracle Server error occurs in any user's session. The DBA creates the following trigger:
CREATE TRIGGER log_errs_trigg
-- Line A
BEGIN
INSERT INTO errlog_table VALUES (...);
END;
What should the DBA code at Line A ?

AFTER ERROR ON DATABASE
AFTER SERVER ERROR ON DATABASE
AFTER SERVERERROR ON SCHEMA
AFTER SERVERERROR ON DATABASE (*)
AFTER ORACLE ERROR ON SCHEMA

34. You want to prevent any objects in your schema from being altered or dropped. You decide to create the following trigger:
CREATE TRIGGER stop_ad_trigg
-- Line A
BEGIN
RAISE_APPLICATION_ERROR(-20203,'Invalid Operation');
END;
What should you code at Line A ?

AFTER ALTER OR DROP ON SCHEMA
INSTEAD OF ALTER OR DROP ON SCHEMA
BEFORE ALTER OR DROP ON SCHEMA (*)
BEFORE ALTER, DROP ON SCHEMA
AFTER ALTER, DROP ON SCHEMA

35. Examine this code:
CREATE TRIGGER de_trigg
-- Line A
BEGIN ...
Which of the following are NOT valid at Line A ? (Choose two.) (Choose all correct answers)
AFTER LOGOFF ON SCHEMA (*)
AFTER LOGON ON SCHEMA
BEFORE LOGOFF ON SCHEMA
BEFORE DISCONNECT ON SCHEMA (*)
AFTER SERVERERROR ON SCHEMA

36. Which of the following statements could cause a DDL trigger to fire?
DROP TABLE employees;

ALTER TABLE departments ADD (budget NUMBER(8,2));
CREATE TABLE newemp AS SELECT * FROM employees;
TRUNCATE TABLE locations;
All of the above (*)

37. Examine this code:
CREATE TRIGGER new_trigg
AFTER CREATE ON reserved_word
BEGIN ...
Which of the following can be used in place of reserved_word? (Choose two.) (Choose all correct answers)
TABLE
SCHEMA (*)
USER
DATABASE (*)
TABLE employees

38. Which kinds of trigger can cause a mutating table problem? (Choose two.) (Choose all correct answers)
BEFORE UPDATE row triggers (*)
DDL triggers
AFTER DELETE row triggers (*)
Database Event triggers
INSTEAD OF triggers

39. Examine the following code:
CREATE TRIGGER emp_trigg
AFTER UPDATE OF salary ON employees
FOR EACH ROW
DECLARE
v_count NUMBER;
BEGIN
-- Line A
END;
Which of the following statements is NOT allowed at Line A?

SELECT count(*) INTO v_count FROM departments;
UPDATE employees SET job_id = 'IT_PROG' WHERE employee_id = : OLD.employee_id;
SELECT count(*) INTO v_count FROM employees; (*)
DBMS_OUTPUT.PUT_LINE('A salary was updated');
None. All of the above are allowed.


40. What is wrong with the following code?
CREATE OR REPLACE TRIGGER loc_trigg
BEFORE DELETE ON locations
BEGIN
RAISE_APPLICATION_ERROR(-20201,'Invalid delete');
ROLLBACK;
END;

The last line should be: END loc_trigg;
You cannot use RAISE_APPLICATION_ERROR inside a trigger.
The second line should be: BEFORE DELETE OF locations
You cannot use ROLLBACK inside a trigger. (*)
Nothing is wrong, this trigger will compile and execute successfully.

41. What is wrong with the following code?
CREATE TRIGGER dept_trigg
BEFORE UPDATE OF department_name ON departments
BEGIN
DBMS_OUTPUT.PUT_LINE(:NEW.department_name);
END;

You cannot use :NEW in a BEFORE trigger, only in an AFTER trigger.
You cannot use :NEW or :OLD in a statement trigger. (*)
You cannot use DBMS_OUTPUT.PUT_LINE inside a trigger.
The second line should be: BEFORE UPDATE ON departments.department_name

42. You need to create a trigger that will fire whenever an employee's s
alary or job_id is updated, but not when any other column of the EMPLOYEES
table is updated. Which of the following is the correct syntax to do this?

CREATE TRIGGER emp_upd_trigg
AFTER UPDATE ON employees (salary, job_id)
BEGIN ...


 CREATE TRIGGER emp_upd_trigg
AFTER UPDATE OF salary, job_id ON employees
BEGIN ...(*)

 CREATE TRIGGER emp_upd_trigg
AFTER UPDATE OF (salary, job_id) ON employees
BEGIN ...

CREATE TRIGGER emp_upd_trigg
AFTER UPDATE OF salary OR job_id ON employees
BEGIN ...

43. The following code will successfully create emp_trigg: True or False?
CREATE OR REPLACE TRIGGER emp_trigg
BEFORE DELETE OF salary ON employees
BEGIN
RAISE_APPLICATION_ERROR(-20202,'Deleting salary is not allowed');
END;

True
False (*)

44. What type of database object would you create to write an auditing record automatically every time a user connects to the database?
A procedure
A complex view
A trigger (*)
A function
A package

45. The following objects have been created in a user's schema:
-a function FUNC1
-A package PACK1 which contains a public procedure PACKPROC and a
private function PACKFUNC
-a trigger TRIGG1.
The procedure and functions each accept a single IN parameter of type NU
MBER, and the functions return BOOLEANs. Which of the following calls to
these objects (from an anonymous block) are correct? (Choose two.) (Choose all correct answers)
pack1.packproc(25); (*)
SELECT func1(100) FROM dual;
trigg1;
IF pack1.packfunc(40) THEN ...
IF func1(75) THEN ... (*)

46. You can use a trigger to prevent rows from being deleted from the EMPLOYEES table on Mondays. True or False?
True (*)
False

47. Which of the following are good guidelines to follow when creating a
database trigger? (Choose two.) (Choose all correct answers)
Where possible, use a trigger to enforce a foreign key constraint.
Use triggers to override privilege checking and view other users' private tables.
Do not use a trigger to replace or duplicate something which the Oracle Server does automatically. (*)
Use triggers to prevent unauthorized users from SELECTing confidential data.
Do not create a trigger that automatically fires another trigger. (*)

48. Which of the following are NOT stored inside the database? (Choose two.) (Choose all correct answers)

 A PL/SQL package specification
A database trigger
An anonymous block (*)
An application trigger (*)
A sequence

49. A business rule states that an employee's salary cannot be greater than 99,999.99 or less than 0. The best way to enforce this rule is by using:
A datatype of NUMBER(7,2) for the SALARY column
A database trigger
A check constraint (*)
An application trigger
A view

50. Which of the following best describes a database trigger?
A subprogram that checks whether a user has typed the correct password to log on to the database.
A PL/SQL subprogram that executes automatically whenever an associated database event occurs. (*)
A PL/SQL subprogram that always returns exactly one value.
A subprogram that is invoked explicitly by the calling application.
A PL/SQL subprogram that inserts rows into a logging table.