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Asked: 2026-06-03T21:00:02+00:00

I have Three Entities School , Department , Program and whenever i tried to

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I have Three Entities School, Department, Program and whenever i tried to Join two of these entities, the third one gets referenced and so i am looking for an example using the criteria builder on how to properly start at a Root<> entity and Join properly.

My School entity is the one causing the problem.

public class School {

@NotNull
private String name;

@NotNull
private String code;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "schoolDepartment")
private Set<Department> departments = new HashSet<Department>();

@OneToMany(cascade = CascadeType.ALL, mappedBy = "school")
private Set<Program> programs = new HashSet<Program>();
}

Program Entity

public class Program {

@NotNull
@Size(min = 0, max = 300)
private String name;

@NotNull
@Size(min = 0)
private String description;

private String code;

@Enumerated(EnumType.STRING)
private ProgramType programType;

@ManyToOne
private School school;

My failing attempt to Only join the two entities above and EclipseLink goes and references the third?

    // FROM program JOIN School 
Root<Program> program = cq.from(Program.class);

Join<School,Program> school =  program.join("school" , JoinType.INNER);
            //Join<School, Department> departmentJoin =    school.join("schoolDepartment", JoinType.LEFT);

             // SELECT task as Task, person as Person, ... 
             cq.multiselect(program,school);
             return program;  // EclipseLink requires a joined entity for the count

The full stack trace which includes the SQL generated. Notice how it starts referencing the School entity and then calls a ReadAllObjectQuery on the Department entity?

[EL Fine]: sql: 2012-05-06 17:34:52.886--ServerSession(1839972036)--Connection(131165903)--Thread(Thread["http-bio-8080"-exec-3,5,main])--SELECT t0.id, t0.CODE, t0.NAME, t0.version, t1.programID, t1.ACTIVE, t1.CODE, t1.DESCRIPTION, t1.NAME, t1.PROGRAMTYPE, t1.REQUIREDCREDITS, t1.version, t1.SCHOOL_id FROM SCHOOL t0 LEFT OUTER JOIN PROGRAM t1 ON (t1.SCHOOL_id = t0.id), SCHOOL t2 WHERE (t2.id = t1.SCHOOL_id)
[EL Finest]: connection: 2012-05-06 17:34:52.888--ServerSession(1839972036)--Connection(354961667)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Connection released to connection pool [read].
2012-05-06 17:34:52,896 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.annotation.InjectionMetadata - Processing injected method of bean 'org.bixin.dugsi.domain.School': PersistenceElement for transient javax.persistence.EntityManager org.bixin.dugsi.domain.School.entityManager
2012-05-06 17:34:52,896 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'entityManagerFactory'
2012-05-06 17:34:52,899 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.annotation.InjectionMetadata - Processing injected method of bean 'org.bixin.dugsi.domain.School': PersistenceElement for transient javax.persistence.EntityManager org.bixin.dugsi.domain.School.entityManager
2012-05-06 17:34:52,900 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'entityManagerFactory'
2012-05-06 17:34:52,901 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.annotation.InjectionMetadata - Processing injected method of bean 'org.bixin.dugsi.domain.School': PersistenceElement for transient javax.persistence.EntityManager org.bixin.dugsi.domain.School.entityManager
2012-05-06 17:34:52,901 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'entityManagerFactory'
2012-05-06 17:34:52,902 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.annotation.InjectionMetadata - Processing injected method of bean 'org.bixin.dugsi.domain.Program': PersistenceElement for transient javax.persistence.EntityManager org.bixin.dugsi.domain.Program.entityManager
2012-05-06 17:34:52,903 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'entityManagerFactory'
[EL Finest]: query: 2012-05-06 17:34:52.904--ServerSession(1839972036)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Execute query ReadObjectQuery(name="school" referenceClass=School )
2012-05-06 17:34:52,908 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.annotation.InjectionMetadata - Processing injected method of bean 'org.bixin.dugsi.domain.Program': PersistenceElement for transient javax.persistence.EntityManager org.bixin.dugsi.domain.Program.entityManager
2012-05-06 17:34:52,908 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'entityManagerFactory'
[EL Finest]: transaction: 2012-05-06 17:34:52.908--UnitOfWork(2138845270)--Thread(Thread["http-bio-8080"-exec-3,5,main])--[EL Finest]: query: 2012-05-06 17:34:52.91--ServerSession(1839972036)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Execute query ReadAllQuery(name="departments" referenceClass=Department )
[EL Finest]: connection: 2012-05-06 17:34:52.911--ServerSession(1839972036)--Connection(32490450)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Connection acquired from connection pool [read].
[EL Finest]: connection: 2012-05-06 17:34:52.911--ServerSession(1839972036)--Thread(Thread["http-bio-8080"-exec-3,5,main])--reconnecting to external connection pool
[EL Fine]: sql: 2012-05-06 17:34:52.912--ServerSession(1839972036)--Connection(606146812)--Thread(Thread["http-bio-8080"-exec-3,5,main])--SELECT id, ACTIVE, CODE, DESCRIPTION, NAME, version, SCHOOLDEPARTMENT_id FROM DEPARTMENT WHERE (SCHOOLDEPARTMENT_id = ?)
    bind => [1]
[EL Finest]: connection: 2012-05-06 17:34:52.913--ServerSession(1839972036)--Connection(32490450)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Connection released to connection pool [read].
2012-05-06 17:34:52,914 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.annotation.InjectionMetadata - Processing injected method of bean 'org.bixin.dugsi.domain.Department': PersistenceElement for transient javax.persistence.EntityManager org.bixin.dugsi.domain.Department.entityManager
2012-05-06 17:34:52,914 ["http-bio-8080"-exec-3] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'entityManagerFactory'
[EL Finest]: query: 2012-05-06 17:34:52.915--ServerSession(1839972036)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Execute query ReadObjectQuery(name="schoolDepartment" referenceClass=School )
[EL Finest]: query: 2012-05-06 17:34:52.915--ServerSession(1839972036)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Execute query ReadAllQuery(name="programs" referenceClass=Program )
[EL Finest]: connection: 2012-05-06 17:34:52.916--ServerSession(1839972036)--Connection(63558014)--Thread(Thread["http-bio-8080"-exec-3,5,main])--Connection acquired from connection pool [read].
[EL Finest]: connection: 2012-05-06 17:34:52.916--ServerSession(1839972036)--Thread(Thread["http-bio-8080"-exec-3,5,main])--reconnecting to external connection pool
[EL Fine]: sql: 2012-05-06 17:34:52.917--ServerSession(1839972036)--Connection(920168739)--Thread(Thread["http-bio-8080"-exec-3,5,main])--SELECT programID, ACTIVE, CODE, DESCRIPTION, NAME, PROGRAMTYPE, REQUIREDCREDITS, version, SCHOOL_id FROM PROGRAM WHERE (SCHOOL_id = ?)
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1 Answer

  1. Editorial Team

    I added fetch = FetchType.Eager to each OneToMany relationships as it was Lazy Loading all referencing entities. Dont know if this is a performance issue or not but i figured i would need those columns anyways

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