R – Pre loading objects in an HQL query

hibernatehql

I'm using the following HQL query to try and load a set of objects when I select a Student object based on the advice found at the following link.
http://www.javalobby.org/articles/hibernate-query-101/

from gradebook.model.Student student where student.studentId=1 left join fetch student.scores

I get the following error.
unexpected token: left near line 1, column 64
I've pasted the relevant section of my mapping file below.

<set name="scores" inverse="true" lazy="true" table="score" fetch="select">
<key>
<column name="student_id" not-null="true" />
</key>
<one-to-many class="gradebook.model.Score" />
</set>

Best Answer

The HQL syntax is wrong. The JOIN clause belongs before the WHERE clause.

The HQL syntax is based on the SQL syntax. If you don't know SQL syntax very well, you may run into trouble with HQL syntax as well. I can recommend you the SQL tutorial at w3schools.com.

Good luck.

Related Solutions

Retrieving and loading third level referenced classes through HQL

You can access it exactly the same way you did with scores; you just need to assign an alias to collection so you can refer to it again:

from Student student
 left join fetch student.scores score
 left join fetch score.gradeEvent
where student.studentId=1

Hibernate HQL: Get count of results without actually returning them

This should do the trick:

select count(*) FROM Company c JOIN ...

There is no sub-select involved, just instead of returning Company, you return the count.

Edit: The FETCH is out of place now. You're not returning the entities from the query, but only the count, thus, Hibernate complains. Removing it should help:

select count(product) from org.myCompany.applicant.entity.Applicant applicant 
    LEFT OUTER JOIN applicant.products product

Best Answer

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Retrieving and loading third level referenced classes through HQL

Hibernate HQL: Get count of results without actually returning them

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