Hibernate oneToMany without mapping or joining











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Is it possible to add a list of Entitys into another Entity without having a mapping or joinColumn?



What I want is something like



EntityA{
@OneToMany
List<EntityX> allEntitiesX
}


This List should behave like



Query query=session.createQuery("from EntityX"); 
List allEntitiesX=query.list();


So if I load the EntiyA I also have acces to all other entities EntityX(with lazy-loading) without "leaving" EntityA. Due to our legacy programm I can not add a new table to connect both Entitys, because I would have to update all existing customer data and teach the old system to handle this joinTable the same way.



If possible beeing able to filter with conditions would be good aswell.



Why I want it:
In our system every "mainEntity" can have properties (EntityX).
Every property entity has a list of values, and these values are mapped with a joinTable to the "mainEntity".
If I want to add a method setProperty(propertyName, value) I have the problem that I cant find the correct propertyEntity to add my value.
The setter would have to be moved to a place where I can do entityManager querys.










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  • It is completely unclear what you are asking.
    – Alan Hay
    Nov 20 at 9:38















up vote
0
down vote

favorite












Is it possible to add a list of Entitys into another Entity without having a mapping or joinColumn?



What I want is something like



EntityA{
@OneToMany
List<EntityX> allEntitiesX
}


This List should behave like



Query query=session.createQuery("from EntityX"); 
List allEntitiesX=query.list();


So if I load the EntiyA I also have acces to all other entities EntityX(with lazy-loading) without "leaving" EntityA. Due to our legacy programm I can not add a new table to connect both Entitys, because I would have to update all existing customer data and teach the old system to handle this joinTable the same way.



If possible beeing able to filter with conditions would be good aswell.



Why I want it:
In our system every "mainEntity" can have properties (EntityX).
Every property entity has a list of values, and these values are mapped with a joinTable to the "mainEntity".
If I want to add a method setProperty(propertyName, value) I have the problem that I cant find the correct propertyEntity to add my value.
The setter would have to be moved to a place where I can do entityManager querys.










share|improve this question
























  • It is completely unclear what you are asking.
    – Alan Hay
    Nov 20 at 9:38













up vote
0
down vote

favorite









up vote
0
down vote

favorite











Is it possible to add a list of Entitys into another Entity without having a mapping or joinColumn?



What I want is something like



EntityA{
@OneToMany
List<EntityX> allEntitiesX
}


This List should behave like



Query query=session.createQuery("from EntityX"); 
List allEntitiesX=query.list();


So if I load the EntiyA I also have acces to all other entities EntityX(with lazy-loading) without "leaving" EntityA. Due to our legacy programm I can not add a new table to connect both Entitys, because I would have to update all existing customer data and teach the old system to handle this joinTable the same way.



If possible beeing able to filter with conditions would be good aswell.



Why I want it:
In our system every "mainEntity" can have properties (EntityX).
Every property entity has a list of values, and these values are mapped with a joinTable to the "mainEntity".
If I want to add a method setProperty(propertyName, value) I have the problem that I cant find the correct propertyEntity to add my value.
The setter would have to be moved to a place where I can do entityManager querys.










share|improve this question















Is it possible to add a list of Entitys into another Entity without having a mapping or joinColumn?



What I want is something like



EntityA{
@OneToMany
List<EntityX> allEntitiesX
}


This List should behave like



Query query=session.createQuery("from EntityX"); 
List allEntitiesX=query.list();


So if I load the EntiyA I also have acces to all other entities EntityX(with lazy-loading) without "leaving" EntityA. Due to our legacy programm I can not add a new table to connect both Entitys, because I would have to update all existing customer data and teach the old system to handle this joinTable the same way.



If possible beeing able to filter with conditions would be good aswell.



Why I want it:
In our system every "mainEntity" can have properties (EntityX).
Every property entity has a list of values, and these values are mapped with a joinTable to the "mainEntity".
If I want to add a method setProperty(propertyName, value) I have the problem that I cant find the correct propertyEntity to add my value.
The setter would have to be moved to a place where I can do entityManager querys.







hibernate jpa






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edited Nov 20 at 15:34

























asked Nov 20 at 8:50









OME

11




11












  • It is completely unclear what you are asking.
    – Alan Hay
    Nov 20 at 9:38


















  • It is completely unclear what you are asking.
    – Alan Hay
    Nov 20 at 9:38
















It is completely unclear what you are asking.
– Alan Hay
Nov 20 at 9:38




It is completely unclear what you are asking.
– Alan Hay
Nov 20 at 9:38












1 Answer
1






active

oldest

votes

















up vote
0
down vote













Yes that is possible but that will create another third table but you actually dont need third table in case of onetomany and manytoone as every row of EntityX will contain one column for EntityA.



The simplest mapping you can do is like below.



EntityA{
@OneToMany(mappedBy="entityA",cascade = CascadeType.ALL,fetch = FetchType.LAZY)
List<EntityX> allEntitiesX
}


And in another entity



EntityX{
@ManyToOne
EntityA entityA;
}





share|improve this answer





















  • Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
    – OME
    Nov 20 at 9:27












  • refer this websystique.com/hibernate/…
    – Alien
    Nov 20 at 9:30











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1 Answer
1






active

oldest

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1 Answer
1






active

oldest

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up vote
0
down vote













Yes that is possible but that will create another third table but you actually dont need third table in case of onetomany and manytoone as every row of EntityX will contain one column for EntityA.



The simplest mapping you can do is like below.



EntityA{
@OneToMany(mappedBy="entityA",cascade = CascadeType.ALL,fetch = FetchType.LAZY)
List<EntityX> allEntitiesX
}


And in another entity



EntityX{
@ManyToOne
EntityA entityA;
}





share|improve this answer





















  • Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
    – OME
    Nov 20 at 9:27












  • refer this websystique.com/hibernate/…
    – Alien
    Nov 20 at 9:30















up vote
0
down vote













Yes that is possible but that will create another third table but you actually dont need third table in case of onetomany and manytoone as every row of EntityX will contain one column for EntityA.



The simplest mapping you can do is like below.



EntityA{
@OneToMany(mappedBy="entityA",cascade = CascadeType.ALL,fetch = FetchType.LAZY)
List<EntityX> allEntitiesX
}


And in another entity



EntityX{
@ManyToOne
EntityA entityA;
}





share|improve this answer





















  • Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
    – OME
    Nov 20 at 9:27












  • refer this websystique.com/hibernate/…
    – Alien
    Nov 20 at 9:30













up vote
0
down vote










up vote
0
down vote









Yes that is possible but that will create another third table but you actually dont need third table in case of onetomany and manytoone as every row of EntityX will contain one column for EntityA.



The simplest mapping you can do is like below.



EntityA{
@OneToMany(mappedBy="entityA",cascade = CascadeType.ALL,fetch = FetchType.LAZY)
List<EntityX> allEntitiesX
}


And in another entity



EntityX{
@ManyToOne
EntityA entityA;
}





share|improve this answer












Yes that is possible but that will create another third table but you actually dont need third table in case of onetomany and manytoone as every row of EntityX will contain one column for EntityA.



The simplest mapping you can do is like below.



EntityA{
@OneToMany(mappedBy="entityA",cascade = CascadeType.ALL,fetch = FetchType.LAZY)
List<EntityX> allEntitiesX
}


And in another entity



EntityX{
@ManyToOne
EntityA entityA;
}






share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 20 at 8:57









Alien

4,48521023




4,48521023












  • Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
    – OME
    Nov 20 at 9:27












  • refer this websystique.com/hibernate/…
    – Alien
    Nov 20 at 9:30


















  • Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
    – OME
    Nov 20 at 9:27












  • refer this websystique.com/hibernate/…
    – Alien
    Nov 20 at 9:30
















Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
– OME
Nov 20 at 9:27






Thank you for the quick answer, but I fear this will not help me because I reality it would be a manyToMany connection (but I need only one direction). Additionaly I cant change the tables because antothes non-JPA system is working on the same database. If the answer in this case is no I will mark this answer as Accepted
– OME
Nov 20 at 9:27














refer this websystique.com/hibernate/…
– Alien
Nov 20 at 9:30




refer this websystique.com/hibernate/…
– Alien
Nov 20 at 9:30


















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