PL/SQL EXAMPLES

-- demonstration of anonymous block
DECLARE
	v_empno emp.empno%type;
	v_name emp.ename%type;
	v_sal emp.sal%type;

	v_real real := 1.234;

BEGIN
	SELECT ename, sal
	INTO v_name, v_sal 	
	FROM emp
	WHERE empno = &v_empno;

	dbms_output.put_line('The salary of ' || v_name ||' is: USD  '||to_char(v_sal));

		dbms_output.put_line('The real is  '||to_char(v_real));
EXCEPTION
	when NO_DATA_FOUND then
		dbms_output.put_line('Could not find any one!');

END;
/
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-- example of implicit cursor: SQL%NOTFOUND
BEGIN
	update emp
	set sal = 5000
	 where empno = &my_empno;
	 IF SQL%NOTFOUND then
	      dbms_output.put_line('could not update anyone');
	 END IF;
END;
/
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create or replace function check_phone(phone varchar2) return number is
begin

-- remove all valid char in "1234567890-()", all invalid chars remained
 if replace(translate(phone,' 1234567890()-','             '),' ') is not null then
     return 0;
 else
    return 1;
 end if;
 end check_phone;

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-- demonstration of function

create or replace FUNCTION square (in_value in number) RETURN number  is
BEGIN
	return (in_value*in_value);
END;
/

select sal, square(sal) from emp;
select square(5) from dual;
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CREATE OR REPLACE FUNCTION get_sal
 (v_id  IN   emp.empno%TYPE)
 RETURN NUMBER
 IS
   v_salary emp.sal%TYPE :=0;
 BEGIN
   SELECT sal
   INTO   v_salary
   FROM   emp
    WHERE   empno = v_id;
    RETURN (v_salary);
 END get_sal;
/

select empno, sal, get_sal(empno) from emp;

VARIABLE G_SAL NUMBER
EXECUTE :G_SAL := GET_SAL(7369);
 PRINT :G_SAL;

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create or replace PROCEDURE TEST_INPUT (IN_NUM IN NUMBER) IS
 V_NUMBER NUMBER := 5;
 V_CHAR VARCHAR2(20);
 BAD_DATA EXCEPTION;

BEGIN
 IF (IN_NUM < 10) THEN
  V_CHAR := 'SMALL NUMBER';
 ELSIF (IN_NUM >= 10 AND IN_NUM < 20) THEN
  V_CHAR := 'GOOD NUMBER';
 ELSE
  V_CHAR := 'BAD DATA FOUND';
  raise BAD_DATA;
 END IF;
  dbms_output.put_line(v_char);

EXCEPTION
 WHEN BAD_DATA THEN
  dbms_output.put_line('error entered number');
END;
/

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CREATE OR REPLACE PROCEDURE query_emp  (v_id     IN	emp.empno%TYPE,
 v_name	  OUT	emp.ename%TYPE,
 v_salary OUT	emp.sal%TYPE,
 v_comm	  OUT	emp.comm%TYPE)
  IS
 BEGIN
   SELECT   ename, sal, comm
   INTO     v_name, v_salary, v_comm
    FROM     emp 
   WHERE    empno = v_id;
  END query_emp;
/

VARIABLE g_name  varchar2(15)
VARIABLE g_salary number
VARIABLE g_comm  number

EXECUTE query_emp (7654, :g_name, :g_salary,:g_comm);

print :g_name;

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CREATE OR REPLACE PROCEDURE format_phone  (v_phone_no IN OUT VARCHAR2)
 IS
 BEGIN
  v_phone_no := '(' || SUBSTR(v_phone_no,1,3) ||
                 ')' || SUBSTR(v_phone_no,4,3) ||
                 '-' || SUBSTR(v_phone_no,7);
  END format_phone;
/

VARIABLE g_phone_no varchar2(15)

BEGIN :g_phone_no := '8006330575'; END;

EXECUTE format_phone (:g_phone_no)


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create or replace PROCEDURE sql_example(empno_num number) IS

	my_empno emp.empno%type;
	my_ename emp.ename%type;

BEGIN
	 DELETE  FROM emp 
		WHERE empno = empno_num;
	
	INSERT INTO emp  (empno, ename) 
		VALUES (1234,'Tran Hung');

	SELECT empno, ename INTO my_empno, my_ename
	FROM emp
	WHERE hiredate = to_date( '01-JAN-81') ;

EXCEPTION
	when DUP_VAL_ON_INDEX then
			dbms_output.put_line('duplicated');			
	 when TOO_MANY_ROWS then
		   dbms_output.put_line('more than one person in 81');
	 when NO_DATA_FOUND then
		   dbms_output.put_line('No data found');

END;

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create or replace procedure test_double_block is

	e_mess char(80);
BEGIN

	DECLARE
		n1 number(4);
	BEGIN
		select empno 
		into n1
		from emp
		--where job = 'TTT';
		where job = 'CLERK';
	EXCEPTION
	when TOO_MANY_ROWS then
			dbms_output.put_line('more than one CLERK person ');
			
	END;

	DECLARE
		n2 number(4);
	BEGIN
		select empno 
		into n2
		from emp
		where job = 'MANAGER';		
	EXCEPTION
	when TOO_MANY_ROWS then
			dbms_output.put_line('more than one MANAGER person ');
	END;

	EXCEPTION
	when OTHERS then
		e_mess := SUBSTR(SQLERRM,1,80);
			dbms_output.put_line('e_mess: ' ||e_mess);
				dbms_output.put_line('e_mess: ' ||SQLERRM);
END;
/
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create PROCEDURE change_sal(p_per_1 NUMBER,p_per_2 NUMBER, p_deptno NUMBER) IS
	CURSOR c_emp IS select empno,sal from emp where deptno=p_deptno;
	r_emp  c_emp%rowtype;
	v_sal NUMBER;
BEGIN
	  OPEN c_emp;
	  LOOP
		  FETCH c_emp INTO r_emp;
		  EXIT WHEN  c_emp%NOTFOUND ;

		   IF r_emp.sal >1000 THEN
			   v_sal:=r_emp.sal*p_per_2;
		   ELSE
			   v_sal:=r_emp.sal*p_per_1;
		   END IF;
		   UPDATE emp
		    SET sal=v_sal
		    WHERE empno=r_emp.empno;
	  END LOOP;
	  CLOSE c_emp;
	  COMMIT;
END;

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create or replace PROCEDURE cursor_test (numRow number) is
	cursor emp_cursor is
	select * from emp
	for update;
BEGIN
	  dbms_output.put_line('ename'||'      '||'empno'||'           '||'sal');
 	 for myEmp in emp_cursor loop
	 	  exit when emp_cursor%ROWCOUNT > numRow or emp_cursor%notfound;
 		  dbms_output.put_line (myEmp.ename||'     '||to_char(myEmp.empno)
 		||  '            '||to_char(myEmp.sal));
 	 	 update emp
 	  	set sal = 5000
 	 	 where current of emp_cursor;
	 end loop;
 	 commit;
END;
/
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create or replace procedure test_cursor_for is
	
BEGIN
	dbms_output.put_line ('empno'||'     '||'ename');
	FOR r_emp IN (select empno, ename from emp where job = 'CLERK')
	LOOP
		dbms_output.put_line (to_char(r_emp.empno)||'       '||r_emp.ename);
	END LOOP;
END;


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-- demonstration of EXCEPTION_INIT PRAGMA
DECLARE
	 null_data EXCEPTION;
	 PRAGMA EXCEPTION_INIT (null_data, -01400);
BEGIN
	insert into emp (empno, ename)
	values (null,'ttt');
 EXCEPTION
	when null_data then
		 dbms_output.put_line('null data found');
END;
/

-------------------------------------------------------------------------------------------------------------------------------------------------------
DECLARE
  My_empno number;
  keep_empno number;
BEGIN
  My_empno := 59694;
  SELECT empno INTO keep_empno
  FROM emp
 WHERE empno = my_empno;
EXCEPTION
	WHEN NO_DATA_FOUND THEN
	DBMS_OUTPUT.PUT_LINE('No Data Found');
END;
/
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CREATE OR REPLACE PACKAGE manage_emp IS

	PROCEDURE add_employee 
		(v_empno NUMBER
		, v_ename varchar2
		,v_job varchar2);
	PROCEDURE rem_employee (v_empno NUMBER);

END manage_emp;
/

CREATE OR REPLACE PACKAGE BODY manage_emp IS

 PROCEDURE add_employee 
		(v_empno NUMBER
		, v_ename varchar2
		,v_job varchar2)	 IS
 BEGIN
  INSERT INTO EMP (empno, ename, job)
  VALUES (v_empno, v_ename, v_job);
 END add_employee;


 PROCEDURE rem_employee (v_empno NUMBER) IS
 BEGIN
  DELETE FROM emp
   WHERE empno = v_empno;
 END rem_employee;

END manage_emp;
/

EXECUTE MANAGE_EMP.ADD_EMPLOYEE(7899,'TRAN MINH','SALESMAN');

 EXECUTE MANAGE_EMP.REM_EMPLOYEE(7876);


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-- CREATE TRIGGER: EXAMPLE

CREATE OR REPLACE TRIGGER insert_on_sunday
BEFORE INSERT ON emp
BEGIN
	IF TO_CHAR(sysdate,'DY')  in ('SAT', 'SUN') then
		dbms_output.put_line('OK, you can INSERT');
	ELSE
		dbms_output.put_line('You can not INSERT');
		RAISE_APPLICATION_ERROR (-20500, 'You may only insert into EMP during normal hours.');

	END IF;
	
END;

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PL/SQL EXERCISESE, 


*** PL/SQL subprograms 1

create or replace PROCEDURE change_emp_sal is
	cursor emp_cursor is
	select * from emp
	for update;
BEGIN
	
 	 for myEmp in emp_cursor loop
	 	  exit when  emp_cursor%notfound;
		
		if myEmp.sal < 1000 then
	 	 	 update emp
 		  	set sal = sal*1.05
 	 		 where current of emp_cursor;
		else
			 update emp
 		  	set sal = sal*1.15
 	 		 where current of emp_cursor;
		end if;

	 end loop;
 	 commit;
END;
/
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*** PL/SQL subprogram: 2
create or replace PROCEDURE five_high_sal IS
 cursor c_five_sal is
  select empno, ename, sal from emp e
  where 5 > (select count(*) from emp where e.sal < sal);
 r_five_sal c_five_sal%rowtype;
BEGIN
  dbms_output.put_line(' ');
 dbms_output.put_line('empno'||'  '||'ename'||'  '||'sal');
 OPEN c_five_sal;
 LOOP
  FETCH c_five_sal INTO r_five_sal;
  EXIT when c_five_sal%NOTFOUND;
  dbms_output.put_line(to_char(r_five_sal.empno)||'    ' || r_five_sal.ename||'   ' ||to_char( r_five_sal.sal));
 END LOOP;
 CLOSE c_five_sal;
EXCEPTION
  when NO_DATA_FOUND then
     dbms_output.put_line('No data found');
 when OTHERS then
  dbms_output.put_line('other error:'||SQLERRM);
END;
/
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**** PL/SQL subprograms: 3

create or replace PROCEDURE sql_update(empno_num number) IS
 my_sal emp.sal%type := 6000;
 update_sig EXCEPTION;
BEGIN
 update emp
 set sal = my_sal
 where empno = empno_num;
 if SQL%NOTFOUND then 
	raise update_sig; 
 end if;
EXCEPTION
 when update_sig then
  dbms_output.put_line('zero row updated');
  when NO_DATA_FOUND then
     dbms_output.put_line('No data found');
 when OTHERS then
  dbms_output.put_line('other error:'||SQLERRM);
END;
/

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select user, sysdate, rowid, rownum from sys.dual;

------------------------------------------------------------------------------------------------- 
PL/SQL Tables:

PL/SQL tables use a primary key to give you array-like access to rows.
Like the size of a database table, size of a PL/SQL table is unconstrained. That is, the number of rows in a PL/SQL table can 
increase dynamicalyy. So, your PL/SQL table grows as new rows are added.

PL/SQL tables can have one column and a primary key, neither of which can be named. The column can belong to any
scalar type, but the primary key must belong to type BINARY_INTEGER. 

DECLARE
	TYPE enameTabTyp IS TABLE OF char(10)
		INDEX BY BINARY_INTEGER;

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

select to_char(hiredate,'YY') year, count(empno) number_of_emps
from emp
group by to_char(hiredate,'YY')
having count(empno) = (select max(count(empno)) from emp group by to_char(hiredate,'YY'))
/

____________________________________________________________________________________________

Packaged Cursors: You can separate a cursor specification from its body for placement in a package by
using the RETURN clause, as the following example:

CREATE PACKAGE EMP_ACTIONS AS
	/* DECLARE CURSOR SPECIFICATION */
	
	CURSOR C1 RETURN EMP%ROWTYPE;
END EMP_ACTIONS;

CREATE PACKAGE BODY emp_actions as
	/* define cursor body */

	CURSOR c1 RETURN emp%ROWTYPE
		SELECT * FROM emp WHERE sal > 3000;

	...
END emp_actions;

That way, you can change the cursor body without changing the cursor specification.
A cursor specification has no SELECT statement because the RETURN clause defines the datatype of the
result value. You can use the %ROWTYPE attribute in a RETURN clause to provide a record type
that represents a row in a database table.