Handling Related objects in Hyperledger composer - hyperledger-composer

Question

Model:
namespace org.acme.model
enum CustomerSegment {
o P
o E
}
asset Account identified by Account_No {
o String Account_No
--> Customer Account_Holder
o String Account_Type
o Integer Balance
}
participant Customer identified by Customer_ID {
o String Customer_ID
o String First_Name
o CustomerSegment Customer_Segment
}
transaction UpdateCustomerSegment{
--> Account A
--> Customer C
}
transaction changeBalance{
--> Account A
o Integer newBalance
}
event UCS_Event{
-->Account A
o String oldsegment
o String newsegment
}
event BalanceChangEvent{
-->Account A
o Integer oldbalance
o Integer newbalance
}
Script:
/**
* Place an order for a vehicle
* #param {org.acme.model.UpdateCustomerSegment} ucs - the transaction that calculated Customer Segment
* #transaction
*/
function UpdateCustomerSegment(ucs)
{
var CustomerID=ucs.C.Customer_ID;
var oldCS=ucs.C.Customer_Segment;
if(ucs.A.Balance>3000)
ucs.C.Customer_Segment="E"
else
ucs.C.Customer_Segment="P"
var cust = getParticipantRegistry('org.acme.model.Customer')
.then(function(participantRegistry){
return participantRegistry.update(ucs.C);
})
.then(function(){
//Emit Event
var event_g= getFactory().newEvent('org.acme.model','UCS_Event');
event_g.A=ucs.A;
event_g.oldsegment=oldCS;
event_g.newsegment=ucs.C.Customer_Segment
emit(event_g);
})
return cust;
}
What I need to do is -
Pass only the Account No. to the transaction.
the transaction should fetch the appropriate Customer - where customer ID is same as Account's Account Holder, and update the Customer's Customer Segment
which I am unable to do. is it even doable. I am new, so not sure.
in the above transaction I am passing both the Account No. and Customer ID
2nd Question
Can we update a Participant & Asset both in the same transaction ? if yes how.
3rd Question:
how to call one transaction from within another.

Answer 1

Your model looks good, now you need to write a Transaction Processor function that subscribes to UpdateCustomerSegment transaction and that implements your logic to change the customer segment of the customer, and then persist the customer.
The basic-sample-network includes a similar simple transaction processor:
/**
* Sample transaction processor function.
* #param {org.acme.sample.SampleTransaction} tx The sample transaction instance.
* #transaction
*/
function sampleTransaction(tx) {
// Save the old value of the asset.
var oldValue = tx.asset.value;
// Update the asset with the new value.
tx.asset.value = tx.newValue;
// Get the asset registry for the asset.
return getAssetRegistry('org.acme.sample.SampleAsset')
.then(function (assetRegistry) {
// Update the asset in the asset registry.
return assetRegistry.update(tx.asset);
})
.then(function () {
// Emit an event for the modified asset.
var event = getFactory().newEvent('org.acme.sample', 'SampleEvent');
event.asset = tx.asset;
event.oldValue = oldValue;
event.newValue = tx.newValue;
emit(event);
});
}