[hibernate-dev] [OGM] storing the column names in the entity keys for K/V stores

[Emmanuel Bernard]

> On 26 Nov 2014, at 12:42, Sanne Grinovero <sanne at hibernate.org> wrote:
> 
> ORDERED_ARRAY_STRATEGY could be an Enum, and give you some flexibility
> among your proposals.  With the current model I'd stick to the Map as
> they are the only one safe enough,

I don’t know what you mean by ordered array strategy and enum.
The rest of the sentence seems to imply that you prefer option 3 even for the single id column case. Correct?

> You make a great point about making it easier to run native queries.
> Is that a new goal we have? It seems we have to define the goals we
> want, as the proper data abstraction goal seems to clash with it.
> I'd rather make a custom Query walker which understand how we store
> things in Infinispan, and keep the safety of our more verbose and less
> efficient storage model. For example an inspection tool connected to
> the grid could choose to not show the "SchemaId" tokens, but use them
> to be able to render the entry in some human understandable way, like
> by adding the column names on a table.

These are not really new goals.
Goal #1: make the most natural mapping as possible as if you were not using the ORM but rather use the tool directly.
Goal #2: expose the native query capabilities as a first class citizen and on equal footing as the JP-QL support to benefit from the specificities of your NoSQL backend.
Non Goal: Hibernate OGM is not in the database business - at least until we explore the polyglot persistence topic :)

Now Goal #1 is a bit blurred by the fact that you could consider the use of a data grid as a secondary and mostly temporary store of a data set persisted elsewhere. I  which case the JPA API prevails as the entry point and how you store the data in the grid is not important. But that’s one use case.

> We didn't mention javax.persistence.IdClass but I assume the same applies.

Yes, IdClass with a specific type are like embeddable ids essentially. And implicit IdClass (forgot what they are called) means that the entity class itself is also the id class.