[hibernate-dev] [OGM] Id generation strategies

[Emmanuel Bernard]

I guess it is particularly questionable to have an identity generator be mapped to an ad-hoc table based generator. Remember the angle we came from: make a JPA application work when storing data in Infinispan. Unlike other datastores, Infinispan has not notion of id generation whatsoever.

sequenceName should map to on of the OgmTableGenetator settings somehow.
valueColumnName is something that I elected no to use because NoSQL we bind to so far do not have a strong schema. And at at given segmentColumnValue only correspond a single value. It would come and bite me if someone for the same segment value had two different value column names to differentiate two different sequence. At which stage, I could invoke the What?! card. But it would make sense to expose that info for datastores like Cassandra.

I am fine if we put the whole subject back on the table and revisit. This code has been written back when I was trying to prove that a brick could not fly.

On 04 Jun 2014, at 15:36, Gunnar Morling <gunnar at hibernate.org> wrote:

> Hi,
> 
> I'm rather confused by the way how OgmIdentityGenerator,
> OgmSequenceGenerator and OgmTableGenerator interact.
> 
> Basically, the first two just delegate to the latter. Now intuitively I'd
> have expected an exception when explicitly using a generation type not
> supported on a given datastore, say @GeneratedValue(strategy =
> GenerationType.SEQUENCE) on MongoDB. But as we always delegate to the table
> strategy, such exception is not raised.
> 
> Also several attributes of generator annotations are ignored; E.g.
> naturally at SequenceGenerator.sequenceName(), but also
> @TableGenerator.valueColumnName.
> 
> What has been the motivation behind this design?
> 
> I guess a change to GridDialect may be required for making explicit which
> strategies are supported on a given backend.
> 
> Thanks,
> 
> --Gunnar
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