Hi all,

I'm wondering why its not possible to fetch an association with an inner join ?

When I define an association with outer-join="true" ( or using FetchMode.EAGER ) hibernate generates: "select from a, b where a.col=b.col(+)"

Defining outer-join="false" produces extra SQL Statements to fetch the association.

Is it not possible to use an inner join ?

Thanks,

Matthias

you can certainly use inner join using HQL queries



lookup 11.3. Associations and joins in the hibernate online docs.

My Problem is that when I'm loading an Object with:

MyObject o = (MyObject)session.load(MyObject.class, pk);

I want to retrieve many-to-one associated Objects eagerly. But this works only with outer join="true". I don't understand why its not possible to load these associatens with an inner join without using HQL.

Suggestion:
It is already possible to define a many-to-one association as not null. Hibernate could use this information to fetch the related object using an inner join for performace optimization.

Thanks

odd, i have an object POF which has 2 many to one mappings. They get loaded by default without using any kind of outer join, and i believe outer-join defaults to false.

can you post your mappings?

Excerpt from Mapping file InvoiceItem.hbm.xml:

...
<many-to-one
name="item"
class="Item"
cascade="none"
outer-join="true"
update="true"
insert="true"
access="property"
column="ITEM_ID"
not-null="true"
/>

<many-to-one
name="stock"
class="Stock"
cascade="none"
outer-join="true"
update="true"
insert="true"
access="property"
column="STOCK_ID"
not-null="true"
/>
...

When outer-join is set to true:
load(IncoiceItem.class,pk); produces 1 SQL Select with outer joins.

When outer-join is set to false:
load(IncoiceItem.class,pk); produces 3 SQL Selects

Thats the behaviour described in "Hibernate in action" Chapter 4 Page 148