Hi I am new to hibernate and I am confused about fetching strategy.
I have two tables with one-to-many relationship (e.g. Person and BankAccounts). According to hibernate reference I should use setFetchMode(FetchMode.JOIN) at runtime instead changing it in xml file. But why related collection is loaded only when I use an outer join? When I use inner join I have to initialize collections explicitly in code, even if only one select is executed to retrieve object and related collection.
And another question - is there some API for criteria to set batch-select and subselect fetching at runtime?

yes u have FetchMode class, there we have differentmodes like
FetchMode.Default
FetchMode.Join
FetchMode.select
FetchMode.subselect

for batch size i dont know using criteria but u can specify in hbm file for collections or class
like

session.createCriteria(person.class)
.setFetchMode("accounts", FetchMode.Join));


and with in the transaction you will get the data from the table even you kept lazy="true"

Thanks for your reply dungakishore,

Class FetchMode has not (according to javadocs) subselect field. You have three choices: default, join, select (lazy and eager are deprecated)
According to hibernate reference fetch strategy should be left in hbm file as is and changed at runtime as needed. But I can't see api to accomplish that.
Using join strategy for optimisation has consequence in duplicated object returned by query and batch and subselect has not.

Another matter is why only left outer join cause related collection loaded eagerly (inner join not)
reffering to my example with person and accounts:

will cause accounts collection loaded in one select with persons but in example below:



accounts collection need to be initalized or you will get LazyInitializationException if you try to refer accounts outside session scope

Hi
anybody ?

Maybe I put my question another way

How in criteria API accomplish following task:

How ? in one select
when ? Eagrly

please help me