How to avoid Duplicate Record Insertion through Transform Map script

[Mannam Praveen]

Hello Everyone 

I had correlation Display on field case table. i had mark coalesce field false. still if anyone case state is open/progress coming with same Correlation Display then it should avoid Duplicate Record Insertion through Transform Map script. how i can achieve it..?

Below code i am using but it still inserting record in to the Table 

//Check record exists for the given u_id

    var gr_case = new GlideRecord('case');

    gr_case.addQuery('correlation_id', source.getValue('u_id'));

    gr_case.addQuery('state', 'IN', '1,10,18');

    gr_case.query();

    //If there is a existing CASE with OPEN status then do not create NEW case send the existing CASE id

    if (gr_case.next()) {

        response.status_message = "CASE " + gr_case.number + " already exists in SNOW with OPEN state for the given TICKET : " + source.getValue('u_id');

        ignore = true;

    }