Write a Pl/sql program to check the given username & password are correct. Display the meaningful messages

create table user_info(uname varchar2(20),

upin varchar2(20));

insert into user_info values('sridhar','sri123');

insert into user_info values('anil','anil123');

insert into user_info values('vivek','vikki123');

insert into user_info values('mahesh','mahi123');

--*Pl/sql Block checks for valid user name & password :

DECLARE

   puser        VARCHAR2 (20) := '&username';

   ppass        VARCHAR2 (20) := '&password';

   TYPE urec IS RECORD (

      u   VARCHAR2 (20),

      p   VARCHAR2 (20)

   );

   TYPE utab IS TABLE OF urec

      INDEX BY BINARY_INTEGER;

   ctr          NUMBER (2)    := 1;

   a            BOOLEAN       := FALSE;

   ut           utab;

   valid_user   EXCEPTION;

BEGIN

   FOR i IN (SELECT uname,

                    upin

               FROM user_info)

   LOOP

      ut (ctr).u       := i.uname;

      ut (ctr).p       := i.upin;

      ctr              := ctr + 1;

   END LOOP;

-- checking for user and password

   FOR k IN 1 .. ut.COUNT

   LOOP

      IF ut (k).u = puser AND ut (k).p = ppass

      THEN

         RAISE valid_user;

      ELSE

         a                := TRUE;

      END IF;

   END LOOP;

   IF a = TRUE

   THEN

      DBMS_OUTPUT.put_line (' Invalid user and password ');

   END IF;

EXCEPTION

   WHEN valid_user

   THEN

      DBMS_OUTPUT.put_line (' Login sucessful ');

END;

/