Exception --> error
user defined
system exception
declare
begin
exception
end
PL/SQL program
take the input (any number ) from user, print the input in reverse order
print the input in reverse order
use length function
for i in reverse 1..length(no)
loop
DBMS_OUTPUT.put_line(i);
end loop;
num1:= num1 || substr(no, i, 1)
for i in reverse 1..length(no)
substr( no, 1, 1 )
eg :
declare
given_number varchar2(5) := '&given_number';
str_length number(2);
reverse_num varchar2(5);
begin
str_length := length(given_number);
for i in reverse 1..str_length
loop
reverse_num := reverse_num || substr(given_number, i, 1);
end loop;
DBMS_OUTPUT.put_line('Given number is : ' || given_number);
DBMS_OUTPUT.put_line('Reverse_number is : || reverse_num);
end;
eg :
2nd method
using MOD() and TRUND() function
MOD(1234, 10) --> 4
reverse_num := reverse_num ||
TRUNC(1234/10) --> 123
eg : LEVEL or MADAM or RACECAR(similarity )
Palindrome
write a program to find the given word is palindrome or not.
substr() for loop
declare
s varchar2(10) := '&s';
temp varchar2(10);
begin
for i in reverse 1..length(s)
loop
temp := temp || substr(s, i, 1);
end loop;
--compare
if temp = s then
DBMS_OUTPUT.put_line('PALINDROME');
else
DBMS_OUTPUT.put_line('NOT PALINDROME');
end if;
end;
WAP(write a program) to calculate the salary
input -->ename, salary
calculate --> net salary = salary + HRA + DA - PF
HRA is --> 10% of salary
DA is --> 30% of salary
PF is --> 8% of salary(if salary < 8000)
PF is --> 10% of salary (if salary > 8000)
output --> net salary
--> PF
--> ename
DECLARE
salary varchar2(10) := '&salary';
ename varchar2(10) := 'ename';
net_salary varchar2(10) := 0;
pf varchar2(10) := 0;
hra varchar2(10) := 0;
da varchar2(10) := 0;
BEGIN
hra := 10%*salary;
da := 30%*salary;
if salary > 800 then
pf := 10%*salary;
else
pf := 8%*salary'
end if;
net_salary := salary + hra + da - pf;
DBMS_OUTPUT.put_line('NET SALARY IS : ' || net_salary);
DBMS_OUTPUT.put_line('PF IS : ' || pf);
DBMS_OUTPUT.put_line('ENAME is : ' || ename);
END;
pre-defined (system defined)
use-defined (user defined)
exception : an identifier in PL/SQL that is used to trap for an abnormal condition. if an error occurs then an exception is raised, the block will terminate and control will pass to the exception handler if present.
declare
num1 number(2) := 10;
num2 number(2) ;
begin
num := 1/0;
exception
when error then
end;
when no_data_found
exceptions :
DUP_VAL_ON_INDEX
NO_DATA_FOUND
VALUE_ERROR
INVALID_CURSOR
TOO_MANY_ROWS
INVALID_NUMBER
declare
begin
exception
when no_data_found then
...
when value_error then
...
when too_many-rows then
...
when others then
...
end;
SQLCODE : returns the error number associated with the exception.
SQLERRM : return the complete error message for the exception, including the error code.
declare
num1 number(3) := 10;
num2 number(3) := 8;
e1 EXCEPTION;
begin
if num1 > num2
--start our exception
RAISE e1;
end if;
exception
when no_data_found then
...
when e1 then
...
end;
note : by declaring your exceptions and then explicitly raising that exception with the raise command.
example of user defined exception
eg :(using exception block)
declare
e1 exception;
sal1 sal.emp%type;
begin
select sal into sal1 from emp
where ename='&ename';
if sal1 < 5000 then
raise e1;
end if;
exception
when e1 then
DBMS_OUTPUT.put_line('Less Salary');
when no_data_found then
DBMS_OUTPUT.put_line('employee not found');
end;
eg : (check exception without exception block)
declare
sal1 emp.sal%type;
begin
select sal into sal1 from emp
where ename='&ename';
if sal < 5000 then
raise_application_error(-20001, 'Less Salary');
end if;
end;
note : whenever you use raise_application_error, you must ensure the error code is bigger than 20001.
declare exception variable
raise exception
when e1 then
eg :
create table test1(a1 varchar2(10) primary key)
WAP to check if the same data is present
we cannot insert the same data
pre-defined / user-defined
eg :
create table test1(a1 varchar2(10) primary key)
declare
abc varchar2(10);
begin
insert into test1 values('&abc');
exception
when dup_val_on_index then
DBMS_OUTPUT.put_line('SAME DATA PRESENT');
end;
value_error