InfoPath Dev

I am new to infopath and submitted this question but could not get any response. I will appreciate if anyone can help me with this problem.
I have created an infopath form based on a data source and searching for an item. when I run the script, it gives message " The conversion of the nvarchar value '021111000000" overflowed an int item maximum integer value exceeded"
When I place the field itemcode on form it takes the data type of simple automatically and does not allow me to change. The data field in database is defined as nvarchar. Any help will be highly appreciated

This seems weird. Maybe you should delete the data connection and re-add it so that the corruption doesn't happen again? If all else fails you can extract the form files and manually edit the schema file for the 2DS. If you need help doing this, reply back.