Hi,
 I have a situation here. I have an object A with differnt fields like user(lookup to  user), location__c(lookup to another object B) and date__c. It also has a field called , lets say value__c field which has to be automatically populated. all the other fields wil be loaded.
  I have another object Audit which is a series of some questions which needs to completed by  user and its value is stored in a field called 'submitted_by__c'., date__c  and a field called location__c(which is a lookup to the object B as above). Now what i want to is whenver any user creates a record in audit object by populating  submitted_by__c and location__c fields , it automatically should add 1 (always keeps adding) to the value__c of object A records but only to those records which are matched up by the fields user__c, date__c and location__c on the object A.
      I was thinking of a trigger. But I am not sure. Please given me any ideas.

Thank you