Handling data in various SAP BW Environments

Dear experts,

This question is based on a new implementation scenario.

As you know, in BW, there are 3 environments: Development, QA and Production.

Once we determine our reporting requirements, we install/develop data flow objects in the Development environment. Once we complete our development, do we bring data from ECC into BW Development? Or, do we transport the objects into QA and then we bring the data from ECC?