Hi Kumar,
Firstly, you need to create related package for developer, then you can grant related member to access corresponding package.
For example,
you can package
hana.demo.p1
hana.demo.p2
hana.demo.p3
In user privilege maintenance perspective, you can click package privilege for each developer.
for D1 grant package hana.demo.p1
for D2 grant package hana.demo.p2
for D3 grant package hana.demo.p3
Besides, you want to control models/views for each developer, then I think that you can do it after complete develop phase.
because, during development, developer maybe co-work together.
If you really want do it in development period, then after developer finished one view, you can grant to this view to this developer in sql privilege, you only choose himself created view to him, by this way, it is only this developer can access it.
Hope this can help you.
Regards,
Jerry