How to check Lower and upper case while duplicate check using trigger

Question

I have below code

public class AccountHandler {

    public static void AccountValidation(list<account> acclist){
        set<string>AccName=new set<string>();
          set<string>dbnameset=new set<string>();
        for(account acc:acclist){
            AccName.add(acc.name);
        }
        for(account acc:[select name from account where name in :AccName])
        {
            dbnameset.add(acc.name);
        }
        for(account acc:acclist){
            if(dbnameset.contains(acc.Name)){
                acc.adderror('you cannot create account with Same name');
            }
        }
    }   
}

But if my existing record is like (BrahmanAccount) and i insert a record with name brahmanAccount then its not checking the duplicate.

Please suggest

test Class

@isTest
private class AccountHandler_Test{
  @testSetup
  static void setupTestData(){
    test.startTest();
    Account account_Obj = new Account(Name = 'Name395', Type = 'Prospect', Match_Billing_Address__c = false);
    Insert account_Obj; 
    test.stopTest();
  }
  static testMethod void test_AccountValidation_UseCase1(){
    List<Account> account_Obj  =  [SELECT Name,Type,Match_Billing_Address__c from Account];
    System.assertEquals(true,account_Obj.size()>0);
    AccountHandler obj01 = new AccountHandler();
    AccountHandler.AccountValidation(account_Obj);
  }
}

Answer 1

You could make both uppercase for the comparison:

for(account acc:[select name from account where name in :AccName])
{
    dbnameset.add(acc.name.toUpperCase());
}
for(account acc:acclist){
    if(dbnameset.contains(acc.Name.toUpperCase())){
        acc.adderror('you cannot create account with Same name');
    }
}

Btw. did you already consider using Duplicate Rules?