How to check the duplicate records are entered in Oracle Detail block at runtime?

At runtime while doing data entry or while saving multiple records entry we need to check the duplicate records are entered or not ,if yes then display an error message for the same.

To check the duplicate records the following method can be used:-

The technique used to solve this problem comes from the Kevin D Clarke’s calculated item famous solution.

It uses two calculated items, one in the data bock and another in a control block.

The first calculated item (:DEPT.MATCH_FOUND) is added to the DEPT block. It contains the formula as follow:

Comparaison(:ctrl.charsave, :dept.deptno||:dept.dname)

Notice in this case,that we want to avoid duplicates on both DEPTNO and DNAME values.

Function COMPARAISON (val1 varchar2, val2 varchar2)

Return number

Is

   answer number := 0;

Begin

   if val1 = val2 then

      answer := 1;

   end if;

   return(answer);

End;

COMPARAISON is a program unit stored in the Forms module.

The two values are compared to each other, then the function returns 1 (a value greatest than 0) if both the values are identical.

The first value (:ctrl.charsave) contains the bakup value of the current record.

The DEPT block must have the following properties setting:

Query all records

YES

The CTRL block must have the following properties setting:

Query all records	YES
Single record	YES
Database data block	NO

The second calculated item (:CTRL.MATCH_FOUND) is added to the CTRL block.

It summarize the values contained in all the rows of the DEPT block (dept.match_found).

If the total is greater than 1, we have two duplicated data.