Does this help in any way :

This is a trigger that throws an exception whenever you want to enter a duplicate product

rigger productDuplicatePreventer on Product__c (before insert, before update) {

    Map<String, Product__c> prodMap = new Map<String, Product__c>();
 
    for(Product__c prod: System.Trigger.new) {

        // Make sure we don't treat an Product that isn't changing during an update as a duplicate. 
        if ((prod.Name != null) && 
             (System.Trigger.isInsert || (prod.Name != System.Trigger.oldMap.get(prod.Id).Name))) {
 
               // Make sure another new product isn't also a duplicate 
               if (prodMap.containsKey(prod.Name)) {
                  prod.Name.addError('Another new Product has this same Product Name'); 
               } else { 
                 prodMap.put(prod.Name, prod); 
               }
         } 
    } 

    // Using a single database query, find all the products in the database that have the same 
    //product Name as any of the product being inserted or updated. 
    for (Product__c prod : [SELECT Name FROM Product__c WHERE Name IN :prodMap.KeySet()]) { 
        Product__c newProd = prodMap.get(prod.Name); 
        newProd.Name.addError('A Product with this Product Name already exists.'); 
    } 
}