Prevent duplicate Insertion of records? [duplicate]

Question

I have written a trigger to remove the duplicate insertions but it allows duplications

please check it once where sholu i mistaken

this is my trigger

trigger DuplicateCateCase on Case(before insert,before update) {

     Set<string> accountname= new Set<string>();
     Set<string> integrationtoo= new Set<string>();


     for(Case cas: Trigger.new)
     {
       accountname.add(cas.Account.Name);
       integrationtoo.add(cas.IntegrationTo__c);

     }

   List<Case> duplicatecaseList = [Select id,Case.Account.Name,IntegrationTo__c,SFType__c From Case where Case.Account.Name= :accountname AND IntegrationTo__c =:integrationtoo];

   Set<string > duplicatecaseIds = new Set<string >();

   for(Case dup: duplicatecaseList )
   {
     duplicatecaseIds .add(dup.Account.Name);
      duplicatecaseIds .add(dup.IntegrationTo__c);
      }

   for(Case s : Trigger.new)
   {
        if(s.Account.Name!=null && s.IntegrationTo__c!=null)
        {
           if(duplicatecaseIds.contains(s.Account.Name) && duplicatecaseIds.contains(s.IntegrationTo__c))
           {
             s.addError('Record already exist with same Name');
           }


        }
   }

}

ThAnks