This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
i am yet to understand the concept of Primary key in EJB. Does that mean i gotta have a n extra field in database to have ejbPrimary key also? Can i omit primary key? if i have a table emo :empid, empname then should i have field for ejb primary key?
1. No. However, each row in the table must be uniquely identifiable 2. Not for Entity Beans 3. Deduce from 2, above! You need not have a single column-key, but you do have to be able to construct a class comprised of columns from the database table that uniquely identify a row. For example, if I had multiple "projects" each of which had "options", but the "option" ID wasn't unique, I'd build the PK from project and option. A primary key need have nothing to do with database keyfields, though often it maps to one for performance reasons. What is important is that the key uniquely identifies an EJB.
An IDE is no substitute for an Intelligent Developer.