Write a trigger on contact object with the DNI number fields. Here DNI__c is unique field on Account object,and DNI__c is also present on contact object. Condition 1 - If Account is exist with the DNI then update the accountId on contact record. Conditi

So basically DNI is present in both (accounts and contacts) if an account DNI matches the one on the contact the. You will update the account field on the contact record?

Did I understand correctly?