Hello.

I'm using hibernate tools to reverse engineer a database's tables into EJB 3.0 compliant objects.

In some many-to-many associations I want one of the sides not to be mapped to an entity, but rather have the other side contain a set of the primary keys belonging to the entities it has a relationship with.

For example, if I have the tables PERSON and LANGUAGE as entity tables, and PERSON_LANGUAGE as the many-to-many table containing both the primary keys of PERSON and LANGUAGE, the desired output would be an @Entity Person containig a Set<Integer> of the primary keys of the languages that person speaks.

If I place something like

<table-filter match-name="LK_.*" exclude="true" />

in reverng.xml, the reverse engineering process generates @Entity java classes for the tables mapping the many-to-many association.

Is there a way in which I can configure the reverse engineering process to obtain the result I want? Any help would be apreciated.

Thanks in advance,

Hugo Oliveira
hugom.oliveira.ext@siemens.com

you could probably tweak the mapping generation/templates to output this; but it is *not* how you should map such things....does not make sense (not even from a performance point of view since lazy references is not more than integers + the option of lazy initializing the object).

Hello Max.

I need this behaviour because some database tables map their entities directly to java enums, and I need their primary key because it contains the respective enum sequence number. Having that I number I can then compare and modify values based on the respective java enum.

Thanks,

Hugo Oliveira
hugom.oliveira.ext@siemens.pt

so why don't you just map them as such and/or do xyz.getId() ?

Hello Max.

Are you talking about puting the enum variable in the entity? If you are, I would really like to know how this is done, since I don't even know it to be possible (remember that the entity objects are being reverse engineered and they must be JPA compatible).

If you are talking about creating entities representing the enum and calling getId on these to compare values, I think it's just cluttering up the object model with unnecessary classes, since the only thing I would need from them would be their primary key number.

Thanks,

Hugo Oliveira
hugom.oliveira.ext@siemens.com

well no matter what you do reveng does not support reverse engineering collection associations as values, only entities.

...so some handtuning is needed for doing specific mappings.