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Vanquish39 Posts: 134	Posted 21:58 Oct 21, 2011 \| Professor, how can I eagerly load a collection without specifying a jpa annotation such as FetchType="eager". Let's say I have a customer class and it has a list of accounts. I want to query all the customers and I want the accounts loaded also. I would use like.... select c from Customer c join c.accounts a... If a session is open, I'm sure the accounts load, but if a session is closed... it doesn't load. I saw some examples specifying ... select c from Customer c join fetch c.accounts a Any recommendations? Thanks
cysun Posts: 2935	Posted 23:56 Oct 21, 2011 \| It should be `select c from Customer c left join fetch c.accounts` a) The difference between `join` and `join fetch` is that `join` returns both objects, while `join fetch` returns only the main object (with the collection loaded of course). b) You should do a `left join fetch` to include the customers who do not have any account. c) FetchType.EAGER only works when you load an object by id. If the object(s) is loaded through a query, you'll have to use join fetch to "eagerly" load a collection. There's an example in CSNS2. Check out the `getUserByUsername()` method in `UserDaoImpl`.

Vanquish39

Posts: 134

Posted 21:58 Oct 21, 2011 |

Professor, how can I eagerly load a collection without specifying a jpa annotation such as FetchType="eager".

Let's say I have a customer class and it has a list of accounts. I want to query all the customers and I want the accounts loaded also. I would use like.... select c from Customer c join c.accounts a... If a session is open, I'm sure the accounts load, but if a session is closed... it doesn't load. I saw some examples specifying ... select c from Customer c join fetch c.accounts a

Any recommendations? Thanks

cysun

Posts: 2935

Posted 23:56 Oct 21, 2011 |

It should be

select c from Customer c left join fetch c.accounts

a) The difference between join and join fetch is that join returns both objects, while join fetch returns only the main object (with the collection loaded of course).

b) You should do a left join fetch to include the customers who do not have any account.

c) FetchType.EAGER only works when you load an object by id. If the object(s) is loaded through a query, you'll have to use join fetch to "eagerly" load a collection.

There's an example in CSNS2. Check out the getUserByUsername() method in UserDaoImpl.