Hi @Retired_mod @above example is for materialized view and also it uses String type and as per documentation DLT, identity column only supports 

1. streaming use case

2. sql syntax  streaming is not supported 

I am not seeing any python example to add column on that fly or update. Also streaming uses inference, I tried to use merge schema but still same issue. If we are able to change schema on the fly for python that should confirm about identity column please