Hi to all... I am using struts to develop a web application. I am using mySQL as my backend database. I have a form namely "testForm" which has 2 fields (1 primary key field). When I am saving something into that database from my form with primary key field as blank, it is saved. But logically it should throw an exception (may be SQLException). In database that blank field value is entered as "". Kindly help me to resolve this problem if anybody has a good explanation.