Hibernate version:3
Code between sessionFactory.openSession() and session.close():

I am using the following code :

List results = session.createCriteria(MyClass.class)
.setProjection( Projections.projectionList()
.add(Property.forName("Property1"))
.add(Property.forName("Property2"))
.add(Property.forName("Property3"))
.addOrder(Order.desc("Property3"))
.addOrder(Order.asc("Property1"))
.list();

It does not return me Objects of type MyClass but returns object of type
Object class of java.Can anyone help me in getting the object of type MYClass only with these particular properties only.Thanks in Advance.:-)

Name and version of the database you are using: Oracle 10G

You probably meant somethings like this:



setProjection() is meant exactly to specify the fields you want to be returned by a query, thereby a Criteria query using it want not return a specific class, but an array (o a list, can't remeber) of the specified fields for each row.

All this, of course, if I'm not wrong: I quit using Criteria because of some problems with border cases. This happened some months ago, so forgive me if my reply can't be more exact.

Giampaolo

If, instead, you meant you want MyClass instances with only that properties loaded, well, you can't get that by Criteria or HQL queries. Even better, you can't get that at all in Hibernate.

You may, however, define some of the properties in your MyClass mappings as "lazy loaded", which means they are effectively loaded only when your code references it. If they will not be referenced, then they will never be loaded.

This may or may not be helpful in order to increse performaces, however. As a rule of thumb, it may help appling lazy loading to "blogs", "clogs" and referred entities, while lazy-loading other field type (integers, floatings, short strings etc) is more prone to decrease performances.

In general, use lazy loading with fields which wouldn't be loaded by a single table SELECT anyway (referred entities on most db engines, as well as "blogs" and "clogs" on some of them).

[quote="g.tomassoni"]If, instead, you meant you want MyClass instances with only that properties loaded, well, you can't get that by Criteria or HQL queries. Even better, you can't get that at all in Hibernate....[quote]


Thanks Giampaolo,

It feels good atlast someone answered my query.And with such details.
I really appreciate you.Thanks a lot...

Hi,
Use ResultTransformers.

List results = session.createCriteria(MyClass.class)
.setProjection( Projections.projectionList()
.add(Property.forName("Property1"))
.add(Property.forName("Property2"))
.add(Property.forName("Property3"))
.addOrder(Order.desc("Property3"))
.addOrder(Order.asc("Property1"))
.setResultTransformer(new AliasToBeanResultTransformer(MyClass.class))
.list();


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[quote="pramodkp"]Hi,
Use ResultTransformers.

[i][color=green]List results = session.createCriteria(MyClass.class)
.setProjection( Projections.projectionList()
.add(Property.forName("Property1"))
.add(Property.forName("Property2"))
.add(Property.forName("Property3"))
.addOrder(Order.desc("Property3"))
.addOrder(Order.asc("Property1"))[b]
.setResultTransformer(new AliasToBeanResultTransformer(MyClass.class))[/b]
.list(); [/color][/i]



Thanks a lot pramod you have solved the problem of my programming carrier.I was very irritated with this problem ,every time i got stuck at this problem only.Thanks thanks thanks.

[quote="pramodkp"]Hi,
Use ResultTransformers.

[i][color=green]List results = session.createCriteria(MyClass.class)
.setProjection( Projections.projectionList()
.add(Property.forName("Property1"))
.add(Property.forName("Property2"))
.add(Property.forName("Property3"))
.addOrder(Order.desc("Property3"))
.addOrder(Order.asc("Property1"))[b]
.setResultTransformer(new AliasToBeanResultTransformer(MyClass.class))[/b]
.list(); [/color][/i]


Thanks a lot pramod you have solved the problem of my programming carrier.I was very irritated with this problem ,every time i got stuck at this problem only.Thanks thanks thanks.