Answer Posted / uday

The best thing would be to create a trigger which checks and not allows duplicate data .

Create or replace trigger trig1
before insert or update on t1
for each row
declare
a number (10);
begin
select count(*) into a from t1 where col2 = :new.col2;
if a >= 1 then
raise_application_error(-20123,'data already present and data will not insert');
elsif a = 0 then
dbms_output.put_line('inserted');
end if;
end;

Explain the use of Merge statement in oracle 11g

591

---

how may join possible between (requisition with purchase order)

1695

---

State the various uses of dbcc command?

544

---

How to loop through data rows in the implicit cursor?

537

---

Explain the use of rows option in exp command.

584

---

---

What do you mean by cdb and pdb in oracle 12c?

633

---

What happens in oracle commit?

561

---

How to pass parameters to procedures?

552

---

Difference between varchar and varchar2 data types?

658

---

How to add a new column to an existing table with a default value?

542

---

How does oracle handle read consistency?

674

---

What is PL/SQL ?

1106

---

why dont we assign not null constraint as table level constraint.

2251

---

Does oracle partitioning improve performance?

546

---

How to experiment a data lock in oracle?

593

---