I have an Oracle database table

Account
-------------
Acct_ID - Integer
Acct_Num - varchar2
Acct_Name - varchar2

I use an Oracle sequence to generate Acct_ID

I have the mapping document set up this way



I wish to use the saveOrUpdate convienence method to insert/update records. What I want to know is how do I initialize my bean's id field? If I use int then I have to initialize it to 0. How will saveOrUpdate know how to issue an insert and use the sequence if the value is already popluated as zero? Won't Hibernate just issue an update? Should I use a java.lang.Integer instead so it can be initialized to null? If yes, how do I map this in the type attribute in the hbm file for the id field? Any guidance on how to handle inserts

I always use the primitive wrappers for my identifier columns. That way, your unsaved value is null. Your bean should leave that field as null when you instantiate it and Hibernate will get the correct value from the sequence on insertion. The saveOrUpdate checks the identifier field before determining whether to do a insert or update based on the unsaved-value property of the identifier (which is null by default for primitive wrappers). If you really must use a primitive, add the unsaved-value="0" in the id definition, e.g.



Most of the time, however, you do not need to specify the type or the unsaved-value, as Hibernate will reflect the mapped class and discover it's types in that manner.