Custom Fields on New Thread?

[Abhik]

Hello,
I want to add two custom text fields on new thread which will be saved to database for that thread while posting that thread.

And, then I want to call those two fields in showthread.

How can I do that?

I already created two text fields using a plugin at newthread_start hook and they are showing on while creating a new thread.

NB: I followed this tutorial, but that one is saving the values with post, not database and that's creating some problems.

Thanks