Dear, When i create a rest api with export_mapping. I want to return objects with GUID. Not find out where to select this field on MessageDefinition and Export mapping. What i can do now is: use a micoflow to get object id and convert this object to a non-persistence object and return. 2nd option is : add a Redundancy property, add a after commit event handler to update this property, Select this Redundancy property in message difinition. But, I think mendix shoud has a simple way to do this, is there? Thanks.
Assuming you use the GUID as key;
The GUID isn't accessible as normal attributes are. My advise is to never use them in integrations as they are internal app properties.
What I would do is, add a autonumber attribute to your entity and use that as key in your integrations