Processing only new records in a batch apex

Question

I want to process only the new records in a batch Apex. We can query the new records in a trigger by Trigger.new . Is there any means by which we can query only the newly created data items and process them in a batch class program? I want to update the records upon their creation. Thanks in advance.

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I want my batch to be running every night, and i need to query all the orders created that date. Next i want to see the opportunites that have those orders, and upsert only them. This i want to do so that the batch query only the newly created data items, since it is currently querying all the data and is taking very long time to finish execution. Here is my code:

Giving its brief description: I am upserting a lookup field Order_History__c which is a link to OrderHistory (API name - Order_History__c) object. ID_Opp_Product_18__c, Sales_Order__c (referencing field in OpportunityLineItem), and Order_History__c are present as Custom Fields and Relationship in OpportunityLineItem.

  global class OrderHistoryBatch implements Database.Batchable<sObject>
  {
      String query;
      //String email;
      global Database.QueryLocator start(Database.BatchableContext BC)
      {
          query = 'select iD, Name from Sales_Order__c'; //need to define query
          return Database.getQueryLocator(query);
      }
      global void execute(Database.BatchableContext BC, List<sObject> scope)
      {
          List<Sales_Order__c> soorders = (List<Sales_Order__c>)scope;
          Map<String, ID> salesOrderMap = new Map<String, ID>();
          for (Sales_Order__c so : soorders) { 
               String s2 = String.valueOf(so.Name); 
               String s1 = s2.mid(2,8); 
               if (s1 != null)  {
                  salesOrderMap.put(s1, so.Id);
               }
      }

  List <OpportunityLineItem> oppLineItems = [select Sales_Order__c,       OpportunityId,ID_Opp_Product_18__c from OpportunityLineItem where Sales_Order__c In   :salesOrderMap.keyset()]; 
    for(OpportunityLineItem oli : oppLineItems)  { 
      ID salesOrderId = salesOrderMap.get(oli.Sales_Order__c);
      oli.Order_History__c = salesOrderId;
      }
    upsert oppLineItems;
      }

  global void finish(Database.BatchableContext BC)
      {

      }
  }

Please can anyone help me out in this. I need to wrap it up and deploy in next couple of hours. Thanks in advance.

Answer 1

You can create a custom Status__c field on the Object, whose records you are processing. You could default Status__c to new and in your Batch Job start method, the query locator could filter on WHERE Status__c = 'New'

Once you've processed the records, you could update the Status__c on all processed records to 'Processed'. (You may want to consider an error status in case some records need to be resubmitted for processing) This will prevent the query locator in start() from picking up already processed records again.