Oracle Database Discussions

hi

My company is in the process of migrating some applications and data from mainframes system to oracle database.
As everything is not being migrated now, they are planning to move some applications and leave the db tables as it is
in mainframes a there are a lot of dependencies on these tables. As a part of that i need to work on the interfacing stuff.
I have a screen in oracle that will input some values to the oracle database.
This values need to be send to mainframes system. There some logic will be implemented based on these values and a db2 table data will be updated.
I need to fetch that client data from the mainframes system back to oracle database tables. My company is not using any 3rd party tools.
Is there any way to do so? Please help me.

Thanks