Oracle Database Discussions

Hi

Do any body have idea regarding missing data or missing constraints after export and import which is done with warnings
Recently i exported one of my schema to another schema which is newly created. While exporting i saw an error Exp-00003 No storage definition found for segment (Some Number,Some number) , i thought that beacuse of clob datatype in the table for which it showed warning and we ignored it . after some days we noticed the constraint primary key missing on the table which the source schema use to have
Do any body have idea why the warning is coming and why it is missing every time i export?
what is the alternative i can go through and take care from now onwards , pls help me ,it is going to be serious issue now.

Thank you
Raj Deep.A