Re: [hibernate-dev] HHH-12125 - @GeneratedValue & 5.3
I just updated the text for the Jira[1].
Specifically, in the section on SEQUENCE and TABLE, at the moment I have
kept the legacy behavior of using "hibernate_sequence" as the name of the
table/sequence - users must opt-in to the behavior of using
`@GeneratedValue#generator` as the sequence/table name. I'm thinking I'd
like to change this though - instead having the default behavior be using
`@GeneratedValue#generator` as the sequence/table name, and migrators
opting-out for the old behavior. I think that is more consistent with how
I generally view these kind of migration settings.
Any objections to making that switch?
[1] https://hibernate.atlassian.net/browse/HHH-12125
On Sat, Nov 25, 2017 at 10:59 AM Vlad Mihalcea <mihalcea.vlad(a)gmail.com>
wrote:
That's a great idea. I stumbled on this issue many times, and
it's very
good to simplify the mapping as you suggested.
+1
Vlad
On Sat, Nov 25, 2017 at 6:18 PM, Steve Ebersole <steve(a)hibernate.org>
wrote:
> The background is all in the Jira, but the crux is this... it is better to
> allow a user to do this:
>
> @GeneratedValue( strategy=SEQUENCE, generator="my_seq")
>
> rather than:
>
> @GeneratedValue( strategy=SEQUENCE, generator="my_seq")
> @SequenceGenerator( name="my_seq", sequenceName="my_seq" )
>
> You can see that `SequenceGenerator` is completely unnecessary in this
> case
> because it adds no new information beyond what is already available on the
> `@GeneratedValue`.
>
> This works great for `GeneratedValue#strategy=SEQUENCE` and
> `GeneratedValue#strategy=TABLE`, however consider this mapping:
>
> @GeneratedValue( strategy=AUTO, generator="increment" )
> @GenericGenerator( name = "increment", strategy = "increment"
)
>
> Here we have the same underlying concern - the `@GenericGenerator` is just
> noise, it adds no additional information. In keeping with the work done
> as
> part of HHH-12125 it would be great to allow users to instead just say:
>
> @GeneratedValue( strategy=AUTO, generator="increment" )
>
> The problem here is that this last one is actually the responsibility of
>
> `org.hibernate.boot.model.IdGeneratorStrategyInterpreter#determineGeneratorName`
> to interpret, but it is not passed the `GeneratedValue#generator` value.
>
> So the easiest solution would be to add an additional parameter to
> `IdGeneratorStrategyInterpreter#determineGeneratorName` for passing in the
> generator name. The concern here is that `IdGeneratorStrategyInterpreter`
> is defined in the API space and could very well have custom impls.
>
> A lesser solution wold be to add checks to the code that calls
> `IdGeneratorStrategyInterpreter#determineGeneratorName` to check for
> "magic" generator names before asking the
> `IdGeneratorStrategyInterpreter`. This is just a very inflexible and
> non-extensible solution, but maybe this works for 5.3 and we can adjust
> `IdGeneratorStrategyInterpreter` as part of 6.0.
>
> Thoughts?
>
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