Why can I only have one field of the type List in my entity class?

HaraldWeber — Thu, 14 Aug 2014 11:32:10 -0400

When I create a new entity class and want to have more than one List in it, Xpert.ivy says: "If an entity class has more than one collection you have to use 'Set' instead of 'List' as type."

I think the JEE Persistence API does not have this limitation.

Persistence Api - Many to Many Relationship

HaraldWeber — Wed, 02 Apr 2014 14:12:20 -0400

Is it possible to declare a many to many relationship in the Entity Class Editor?

Persistence Api - Foreign Key is always null

HaraldWeber — Wed, 26 Mar 2014 10:25:39 -0400

currently i'm trying to use the persistence api. I stuck at inserting a one to many relationship. The problem is that the foreign key is always null.

I have two entity classes. User and Option.

User

Name	Type	DB Field	Persistent	Length	Properties	Association	Cascade	Mapped by
id	Integer	id	yes		id, generated
name	String	name	yes	255
opts	Listy<Option>		yes			ONE_TO_MANY	persist, merge	user_fk

Option

Name	Type	DB Field	Persistent	Length	Properties	Association	Cascade
id	Integer	id	yes		id, generated
option	String	opt_value	yes	255
user_fk	User	user_fk	yes		not nullable	MANY_TO_ONE	persist, merge

The Option Objects are created from strings by a converter from a p:selectManyCheckbox. The field user_fk is not set manually in this converter because i don't have a reference to the User object in the converter.

Xpert.ivy creates an entity class for User and adds a "setOpts(List)" method for me.

public void setOpts(java.util.List< persistenceTest.Option > _opts) { opts = _opts; }

If there where a "addOpt(Option) method I could add the reference to User myself.

public void addOpt(persistenceTest.Option __opts) { _opts.setUser_fk(this); optsList.add(_opts); }

Am I thinking wrong or is it not possible to automate the creation of foreign keys?

Best Regards Harald

Questions Tagged With persistence

Why can I only have one field of the type List in my entity class?

Persistence Api - Many to Many Relationship

Persistence Api - Foreign Key is always null

User

Option