New to Hibernate here. Confused with the transaction...
Is there any difference b/w
begin a transaction, select, update
and select, begin transaction, update?





Thanks!

Correct me if I'm wrong - I think Transaction means "unit of work" - either everything is done, or nothing. So, because SELECT does not change any data, in this example there is no difference between these 2 options. More often you will have several data changing operations, eg. UPDATE and DELETE united within a transaction.

Thank you for your reply.
I am new to Hibernate and I thought they are the same.
But I got DB lock wait timeout a lot lately, and I'm trying to figure it out what I did wrong in the code.
The transactions are not big when updating or inserting, but there are constantly a lot of SELECT on every request on the same table.
I am not sure if high volumn of SELECT with occasional UPDATE or INSERT would lock the table.

Some databases have SELECT locks too, this might be your case. I would suggest using SELECT outside transaction. YMMV tho

In case of "Select" being used before "Update" in your cases (i) and (ii) doesn't make a difference.However it might be different if u'r select statement follows an update statement and both update & select accesses the same table/resultset.

Thanks for the reply. Can you please tell me what the difference?