[hibernate-dev] Mapping JPA's @MapKeyEnumerated and @Enumerated on native-enum supporting datastores

[Gunnar Morling]

How about having a custom @Enumerated annotation which offers NATIVE as an
additional choice?

2016-08-26 10:16 GMT+02:00 Emmanuel Bernard <emmanuel at hibernate.org>:

> Can you give HotRod's example of native enum - I imagine Protobuf ?
>
> The issue I see is that ordinal could be an acceptable explicit decision
> that would not be available to the user if you use default as native.
>
> I'm tempted to go native all the time at the detriment of people that
> need high customization.
>
> Emmanuel
>
> On Mon 2016-08-15 18:14, Sanne Grinovero wrote:
> > In the context of Hibernate OGM, it turns out that some datastores
> > have a rather nice "native" support for enums.
> >
> > We aim to map each property of the user's domain model to its most
> > appropriate "physical type", unless the choice is overriden by the an
> > explicit user request.
> >
> > In the case of an Enum, JPA annotations such as @Enumerated have an
> > attribute EnumType to choose the physical representation:
> >
> > public enum EnumType {
> >     /** Persist enumerated type property or field as an integer. */
> >     ORDINAL,
> >
> >     /** Persist enumerated type property or field as a string. */
> >     STRING
> > }
> >
> > However, there's no support for a "NATIVE". Also, the annotation
> > specifies that "ORDINAL" is the default value so I can't just assume
> > that the user didn't specify anything and we're good to use our own
> > NATIVE implementation.
> >
> > Assuming that we can't change the JPA spec, any suggestion on when I
> > could have the Hot Rod dialect for OGM to actually produce a "nice"
> > mapping into native enums?
> >
> > I'm tempted to just use natives all the time; In the case in which the
> > user opted for "STRING" I could drop a warning - or decide to honour
> > that - but in case of ORDINAL I just can't tell if it's a default
> > choice or not so I think a warning would be too much.
> >
> > Another alternative would be that I "go native" when the @Enumerated
> > annotation isn't specified at all: looks like this mapping is valid
> > according to ORM as it seems to treat it as if there was an implicit
> > @Enumerated annotation; I'm not happy about having to rely on people
> > to not use an explicit annotation though.
> >
> > Thanks,
> > Sanne
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