JPA Hibernate, Lazy loading after a Join
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I need to get a entity and its collection from a Rest controler but I have a very strange behaviour with spring data JPA.
I have a ManyToMany relation beetween to entities with a Lazy loading.
@Entity
class Folder{
...
@ManyToMany(fetch = FetchType.LAZY)
protected Set<Tag> tags;
...getter setter
}
@Entity class Tag{
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "tags"
protected List<File> files;
}
And a JPQL query in a spring jpa repository
@Query("SELECT f FROM Folder f INNER JOIN f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
So the Folder is supposed to be populated with the Tag collection and avoid the lazy loading part.
But I can see in the logs that after the Join Query
there is a select on the Tag table, so a lazy loading.
Hibernate: select folder0_.id as id2_2_...
Hibernate: select tags0_.files_id ...
I don't want to use fetch type EAGER because I don't always need the Tag collection. How can I avoid that Lazy loading ?
hibernate jpa spring-data-jpa
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
|
show 1 more comment
I need to get a entity and its collection from a Rest controler but I have a very strange behaviour with spring data JPA.
I have a ManyToMany relation beetween to entities with a Lazy loading.
@Entity
class Folder{
...
@ManyToMany(fetch = FetchType.LAZY)
protected Set<Tag> tags;
...getter setter
}
@Entity class Tag{
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "tags"
protected List<File> files;
}
And a JPQL query in a spring jpa repository
@Query("SELECT f FROM Folder f INNER JOIN f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
So the Folder is supposed to be populated with the Tag collection and avoid the lazy loading part.
But I can see in the logs that after the Join Query
there is a select on the Tag table, so a lazy loading.
Hibernate: select folder0_.id as id2_2_...
Hibernate: select tags0_.files_id ...
I don't want to use fetch type EAGER because I don't always need the Tag collection. How can I avoid that Lazy loading ?
hibernate jpa spring-data-jpa
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
Specify a fetch join: docs.oracle.com/html/E13946_01/…
– Alan Hay
Nov 26 '18 at 15:18
thank you next time I'll RTFM
– Kaizokun
Nov 26 '18 at 16:02
@AlanHay and Kaizokun: I read the linked doku, but I can't understand the use case in oracles example
– JimHawkins
Nov 27 '18 at 6:57
@JimHawkins : what don't u understand exactly ?
– Kaizokun
Nov 27 '18 at 9:36
what I read in oracles example is this: the query returns 5 references to the mag azinewith id 1 . Why is this useful?
– JimHawkins
Nov 27 '18 at 18:59
|
show 1 more comment
I need to get a entity and its collection from a Rest controler but I have a very strange behaviour with spring data JPA.
I have a ManyToMany relation beetween to entities with a Lazy loading.
@Entity
class Folder{
...
@ManyToMany(fetch = FetchType.LAZY)
protected Set<Tag> tags;
...getter setter
}
@Entity class Tag{
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "tags"
protected List<File> files;
}
And a JPQL query in a spring jpa repository
@Query("SELECT f FROM Folder f INNER JOIN f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
So the Folder is supposed to be populated with the Tag collection and avoid the lazy loading part.
But I can see in the logs that after the Join Query
there is a select on the Tag table, so a lazy loading.
Hibernate: select folder0_.id as id2_2_...
Hibernate: select tags0_.files_id ...
I don't want to use fetch type EAGER because I don't always need the Tag collection. How can I avoid that Lazy loading ?
hibernate jpa spring-data-jpa
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
I need to get a entity and its collection from a Rest controler but I have a very strange behaviour with spring data JPA.
I have a ManyToMany relation beetween to entities with a Lazy loading.
@Entity
class Folder{
...
@ManyToMany(fetch = FetchType.LAZY)
protected Set<Tag> tags;
...getter setter
}
@Entity class Tag{
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "tags"
protected List<File> files;
}
And a JPQL query in a spring jpa repository
@Query("SELECT f FROM Folder f INNER JOIN f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
So the Folder is supposed to be populated with the Tag collection and avoid the lazy loading part.
But I can see in the logs that after the Join Query
there is a select on the Tag table, so a lazy loading.
Hibernate: select folder0_.id as id2_2_...
Hibernate: select tags0_.files_id ...
I don't want to use fetch type EAGER because I don't always need the Tag collection. How can I avoid that Lazy loading ?
hibernate jpa spring-data-jpa
hibernate jpa spring-data-jpa
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
asked Nov 26 '18 at 13:58
KaizokunKaizokun
74111
74111
Specify a fetch join: docs.oracle.com/html/E13946_01/…
– Alan Hay
Nov 26 '18 at 15:18
thank you next time I'll RTFM
– Kaizokun
Nov 26 '18 at 16:02
@AlanHay and Kaizokun: I read the linked doku, but I can't understand the use case in oracles example
– JimHawkins
Nov 27 '18 at 6:57
@JimHawkins : what don't u understand exactly ?
– Kaizokun
Nov 27 '18 at 9:36
what I read in oracles example is this: the query returns 5 references to the mag azinewith id 1 . Why is this useful?
– JimHawkins
Nov 27 '18 at 18:59
|
show 1 more comment
Specify a fetch join: docs.oracle.com/html/E13946_01/…
– Alan Hay
Nov 26 '18 at 15:18
thank you next time I'll RTFM
– Kaizokun
Nov 26 '18 at 16:02
@AlanHay and Kaizokun: I read the linked doku, but I can't understand the use case in oracles example
– JimHawkins
Nov 27 '18 at 6:57
@JimHawkins : what don't u understand exactly ?
– Kaizokun
Nov 27 '18 at 9:36
what I read in oracles example is this: the query returns 5 references to the mag azinewith id 1 . Why is this useful?
– JimHawkins
Nov 27 '18 at 18:59
Specify a fetch join: docs.oracle.com/html/E13946_01/…
– Alan Hay
Nov 26 '18 at 15:18
Specify a fetch join: docs.oracle.com/html/E13946_01/…
– Alan Hay
Nov 26 '18 at 15:18
thank you next time I'll RTFM
– Kaizokun
Nov 26 '18 at 16:02
thank you next time I'll RTFM
– Kaizokun
Nov 26 '18 at 16:02
@AlanHay and Kaizokun: I read the linked doku, but I can't understand the use case in oracles example
– JimHawkins
Nov 27 '18 at 6:57
@AlanHay and Kaizokun: I read the linked doku, but I can't understand the use case in oracles example
– JimHawkins
Nov 27 '18 at 6:57
@JimHawkins : what don't u understand exactly ?
– Kaizokun
Nov 27 '18 at 9:36
@JimHawkins : what don't u understand exactly ?
– Kaizokun
Nov 27 '18 at 9:36
what I read in oracles example is this: the query returns 5 references to the mag azinewith id 1 . Why is this useful?
– JimHawkins
Nov 27 '18 at 18:59
what I read in oracles example is this: the query returns 5 references to the mag azinewith id 1 . Why is this useful?
– JimHawkins
Nov 27 '18 at 18:59
|
show 1 more comment
1 Answer
1
active
oldest
votes
Thanks to Alan Hay. The solution is simple we just need to use the Fetch keyword. In order to populate the collection.
@Query("SELECT f FROM Folder f LEFT JOIN FETCH f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
add a comment |
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks to Alan Hay. The solution is simple we just need to use the Fetch keyword. In order to populate the collection.
@Query("SELECT f FROM Folder f LEFT JOIN FETCH f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
add a comment |
Thanks to Alan Hay. The solution is simple we just need to use the Fetch keyword. In order to populate the collection.
@Query("SELECT f FROM Folder f LEFT JOIN FETCH f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
add a comment |
Thanks to Alan Hay. The solution is simple we just need to use the Fetch keyword. In order to populate the collection.
@Query("SELECT f FROM Folder f LEFT JOIN FETCH f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
Thanks to Alan Hay. The solution is simple we just need to use the Fetch keyword. In order to populate the collection.
@Query("SELECT f FROM Folder f LEFT JOIN FETCH f.tags t WHERE
f.id = :id")
Folder findFolderById(@Param("id") int id);
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
answered Nov 27 '18 at 9:36
KaizokunKaizokun
74111
74111
add a comment |
add a comment |
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Specify a fetch join: docs.oracle.com/html/E13946_01/…
– Alan Hay
Nov 26 '18 at 15:18
thank you next time I'll RTFM
– Kaizokun
Nov 26 '18 at 16:02
@AlanHay and Kaizokun: I read the linked doku, but I can't understand the use case in oracles example
– JimHawkins
Nov 27 '18 at 6:57
@JimHawkins : what don't u understand exactly ?
– Kaizokun
Nov 27 '18 at 9:36
what I read in oracles example is this: the query returns 5 references to the mag azinewith id 1 . Why is this useful?
– JimHawkins
Nov 27 '18 at 18:59