Hi All,
I have a scenario in which I want to fetch all the Student data into a Student class.
The structure ot Student class is as follows

Student
RollNo
Name
SubjectId
Subject


My table Structure is
Student
RollNo[PK]
Name
SubjectId[FK- Refers Subject.]

Subject
SubjectId[PK]
Subject


I tried to use join
<class name="Student" table="Student">
<id name="RollNo">
<generator class="assigned">
</id>
<property name="Name">
<property name="SubjectId">
<join table="Subject">
<key property-ref="SubjectId"/>
<property name="Subject">
</join>
</class>
What it does is it tries to match SubjectId with the RollNo
ie. Student.RollNo=Subject.SubjectId.

But I want it to match the SubjectId
ie.Student.StudentId=Subject.SubjectId

I am using <many-to-one> relationship now.
But what it does is its firing many queries which I dont want. It first finds out all the StudentIds then it fires the same no of queries as there are students and searches for Subjects for each student. I want to avoid this.

But in simple JDBC I can get all the data using a single join statement.
Is there any method by which I can optimize the data fetch or is there any method where I can join the two tables?

Please help me
Regards
Manjit.

you will need the <one-to-one> from Student to Subject :)

http://www.hibernate.org/hib_docs/v3/re ... n-onetoone