i custom a primary key id, it's data type is int .

i need it automatically increase when new data is inserted


which generator in hibernate i should choose? increment/identity/sequence/hilo....... . i try every one ,either throw errors or can't increase


help me

All the options are descrobed at http://www.hibernate.org/hib_docs/reference/html_single/#or-mapping-s1-4.

Are you looking for a simple in-memory generation strategy, or globally-unique generation? If the second, what type of database are you using?

my database type is mysql

can you explain what is in-memory generation strategy and globally-unique generation and how do i resolve



i saw the document ,but can't accurately make a choose between all of the generator . can you explain it for me in detail ?


thanks you very much

In memory means just that. The id generation strategy use some process within that JVM to determine a unique id; although, here the id is only unique to the given JVM. So if you have some sort of clustered environment, or two seperate apps using hibernate on the same same database there is the possibility of duplicating ids.

Global id generation generally depend on the DB for help in ensuring more strict uniqueness. MySQL supports identity columns, and so this would be the choice for this type of strategy of MySQL.

You mentioned you had tried identity. What was the problem you had with that?

yes it is ok! thanks