Hibernate HQL: Many to many

Question

I have 2 tables represented by 2 beans:ProcessType and Typology.

On the DB there is a third table that represent the many to many realtion between those two tables, the table doesen't have a bean and is called process_type_typology

The table has 2 columns: typology and process_type

On ProcessType i have the following attribute that represents the relation:

          @ManyToMany(fetch = FetchType.LAZY)
          @JoinTable(name = "process_types_typology" ,
             joinColumns = {@JoinColumn(name = "process_type")} ,
             inverseJoinColumns = {@JoinColumn(name = "typology")})
          private Set<Typology> typologies = new HashSet<Typology>(0);

And then on Typology:

          @ManyToMany(fetch = FetchType.LAZY)
          @JoinTable(name = "process_types_typology" ,
             joinColumns = {@JoinColumn(name = "typology")} ,
             inverseJoinColumns = {@JoinColumn(name = "process_type")})
          private Set<ProcessType> processTypes = new HashSet<ProcessType>(0);

How can i make a join between those 2 tables? The third table is not mapped so i dont' have idea.

On SQL the query is this:

 from processType inner join process_types_typology ptt on pt.id_process_type=ptt_.process_type

score 0 · Answer 1 · edited May 23 '17 at 12:32

0

Just join ProcessType and Typology, Hibernate will take care to mention relationship table in the generated SQL:

from ProcessType pt join pt.typologies t

Also, since the association is bidirectional, make sure to declare one side to be inverse.

edited May 23 '17 at 12:32

Community

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answered Sep 23 '16 at 15:27

Dragan Bozanovic

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Hibernate HQL: Many to many

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