InfoPath Dev

I am using one combobox,i m fetching data from from another list through secondary data connection. I want to add one rule,which will check ,suppose in dropdown options are a,b,c, someone will write d in combobox,d will added in secondary list only when that is not present in master list. How to do that. Ultimately i want to check wheter new value is present in secondary connection or not. Thank you in advance

Hi-

Here's a blog post that explains the options if you'd like to map data into a SharePoint List.

http://forums.qdabra.com/2013/05/map-infopath-form-data-to-a-sharepoint-list/

 Good luck!