[SalesForce] Approval Process: What status’ indicate the record is Submitted for Approval

As far as i remember there are no specific standard REST API to carry approval process.

Having said above one way to achieve this functionality is use apex approval process classes and methods and then use restful apex to form custom REST API's .

http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_process.htm

http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_rest_code_sample_basic.htm

The combination of both apex approval processing classes and Restful apex can be used to achieve your requirements.The links above is helpful to get started on this

What's happening here is that because your code is running in the same execution context as the update to the record that initiated the approval process, the DML for it hasn't been "committed" to the database. See Order of Execution in the Apex Developer Guide to help you follow along with what's happening.

After any Before Insert/Update Triggers, Validation and Duplicate Record Rules run on the record being submitting for approval. The record is then "conditionally saved" to the database. It's a tentative save, not a "commit" to the database. It's at this point I'd expect to see the code for the Approval Process to be initiated (see Approval Processing in the Apex Developer Guide).

This is also the point in the execution context when the After Update trigger will fire. Note that both of these processes happen in the same execution context. In the execution context of the record being submitted for approval, it's not going to be committed to the database, until long after the AfterUpdate trigger has finished running. Workflow, Processes, and numerous other things will be run against the record before the update is "committed" to the database 12 steps in the order of execution later!

At this point, should something happen, the entire Save can still be rolled back for both the record being submitted and insertion of the new Approval Process Instance. As such, it's not possible to query an Id for the latter during the same execution context.

Initiating an Approval Process is what sets the status to 'Started'. It won't be until a successful ProcessResult operation completes that a query will be returned with results that show it as 'Pending'.

What you could do to work around this, is use an @future call to move the query to an asynchronous method that later updates the new custom object record at a later time. Have the method run the query to retrieve the Id of the approval process instance and update the new record on the custom object with it.

You may also want to consider moving most all of this to an asynchronous process since it doesn't sound as though it's something you need immediate updates on.