[hibernate-dev] SchemaManagementTool changes for 5.1 (was Re: 5.1 tentative release date)

[Steve Ebersole]

I also plan on adding an @Incubating annotation for just such things :)

Anyway, I will start on this today.  It will take a few days though I
think.  I'll let you know when I have something ready to look at.

P.S.  Do you agree with what I said on your PR wrt TargetBase?


On Fri, Jan 29, 2016 at 10:15 AM Gunnar Morling <gunnar at hibernate.org>
wrote:

> Hi Steve,
>
> What you suggest sounds good. I've added a comment to
> https://hibernate.atlassian.net/browse/HHH-10458 itself.
>
> The reason why I didn't go for this from the beginning just was that I
> didn't want to break the contract of SchemaCreator and the other
> delegates.
>
> --Gunnar
>
>
>
>
> 2016-01-28 19:27 GMT+01:00 Steve Ebersole <steve at hibernate.org>:
> > For this to work will require some significant changes.  The main one
> being
> > to combine JPA's support for schema generation along
> > with SchemaManagementTool.  The reason being simply that I will need to
> > encapsulate the interpretation of all these settings behind
> > the SchemaManagementTool facade in order for things to properly
> > replace SchemaManagementTool as Gunnar suggests.
> >
> > I am starting this work now on top of the work Gunnar has already done on
> > the PR he sent[1].  But that work is just the tip of the iceberg.  So if
> > you have input to this, speak soon.
> >
> >
> > [1] https://github.com/hibernate/hibernate-orm/pull/1231
> >
> > On Wed, Jan 20, 2016 at 6:13 AM Gunnar Morling <gunnar at hibernate.org>
> wrote:
> >
> >> I went for the proposed intermediary step to avoid breaking the API of
> >> SchemaManagementTool and its delegates. If you have a way for not
> >> breaking the API or think breaking it is alright, then +1 for doing
> >> the ProperSolution™ in 5.1.
> >>
> >> What would it comprise, changing the delegate methods such as
> >> doCreate() to expect a single parameter object providing all the
> >> required info? Target could be a part of this, just an enum probably,
> >> based on wich delegates would do their thing. If it's that, I can try
> >> and help out with it.
> >>
> >> Regarding the release schedule, I'd personally be fine with pushing it
> >> a bit back, but then I don't know whether there are any other hard
> >> timelines to be met.
> >>
> >>
> >> 2016-01-19 16:25 GMT+01:00 Steve Ebersole <steve at hibernate.org>:
> >> > I'd like to get this work into 5.1.  But, as much as possible, I'd
> like
> >> to
> >> > get the ProperSolution in place rather than just a
> >> StepInTheRightDirection.
> >> > If we need to push this date 2-4 weeks I am ok with that.  That would
> >> help
> >> > us coordinate with Infinispan 8.2 schedule (iiuc) for
> >> hibernate-infinispan,
> >> > not to mention I still have to review the work Vlad has done on the
> docs
> >> > again as well as polish the load-by-multi-id API[1].
> >> >
> >> > [1] Sanne still waiting on your feedback to the open question of
> internal
> >> > routing of those calls.
> >> >
> >> > On Tue, Jan 19, 2016 at 8:41 AM Gunnar Morling <gunnar at hibernate.org>
> >> wrote:
> >> >>
> >> >> Hi Steve,
> >> >>
> >> >> As discussed on IRC, I tried plugging in my own SchemaManagementTool
> >> >> and delegates and letting them do the initialization work required
> for
> >> >> OGM.
> >> >>
> >> >> I am hitting a wall though when it comes to the usage in the
> >> >> SchemaExport controller: As it's invoking doCreate() and doDrop()
> >> >> right in the constructor with a "fake" target for delegating the SQL
> >> >> statements, I am bitten by the fact that SchemaExport is instantiated
> >> >> twice in SessionFactoryImpl (once for create, once for drop at
> >> >> shutdown), so I see to invocations to doCreate() and doDrop(). Also I
> >> >> am lacking the knowledge of what's passed as Target for the
> controller
> >> >> invocation.
> >> >>
> >> >> So I went ahead and changed SchemaExport to invoke SchemaCreator and
> >> >> -Dropper only in execute(), passing them actual Target
> implementations
> >> >> as it's done in SchemaUpdate, too. It's not yet what you described as
> >> >> the ultimate goal (not looping back to Target), but IMO it's a step
> >> >> into the right direction, not the least making things consistent
> >> >> between SchemaExport and SchemaUpdate and also leaving APIs largely
> >> >> unchanged for the time being. With that I should be able to do it on
> >> >> the OGM side as you suggested, essentially ignoring the
> >> >> Target/Exporter stuff.
> >> >>
> >> >> I've filed ORM PR
> https://github.com/hibernate/hibernate-orm/pull/1231
> >> >> for the change. Let me know what you think.
> >> >>
> >> >> Cheers,
> >> >>
> >> >> --Gunnar
> >> >>
> >> >>
> >> >> 2016-01-14 15:51 GMT+01:00 Steve Ebersole <steve at hibernate.org>:
> >> >> > I am not sure I am a big fan of The String->Object change
> >> specifically.
> >> >> > In
> >> >> > theory it sounds great.  But there is a major premise in schema
> >> tooling
> >> >> > around the idea of the actions being reduce-able to Strings.
> That's
> >> >> > important not just for SQL, but for the idea of writing to a file
> as
> >> >> > well.
> >> >> > It also affects the whole concept of Exporter/Exportable.
> >> >> >
> >> >> > The ultimate design goal here is to unify schema creation and
> dropping
> >> >> > across native and JPA requirements.  I just simply have not had the
> >> time
> >> >> > to
> >> >> > work on that.  This would all happen "behind" SchemaManagementTool
> and
> >> >> > friends.  SchemaExport, etc are actually just controllers
> responsible
> >> >> > for
> >> >> > coordinating the calls into the SchemaManagementTool delegates.
> The
> >> >> > main
> >> >> > problem at the moment IMO is that Target gets passed into these
> >> >> > SchemaManagementTool delegates.  Ideally, and certainly this would
> fit
> >> >> > with
> >> >> > your case, I think we want SchemaManagementTool or its delegates to
> >> >> > handle
> >> >> > interpreting the "arguments".  This was part of the intent of
> >> developing
> >> >> > the "CommandLineArgs" stuff that is used inside SchemaExport, etc
> now;
> >> >> > the
> >> >> > idea was to encapsulate the settings each tool needs to operate and
> >> >> > isolate
> >> >> > the process of building/interpreting those args.
> >> >> >
> >> >> > The next step I wanted to look at there was to morph
> CommandLineArgs
> >> >> > into a
> >> >> > more generic "parameter object" for initializing the actual
> >> >> > SchemaManagementTool delegates.
> >> >> >
> >> >> > The idea is that the more we can push into SchemaManagementTool and
> >> its
> >> >> > delegates the more pluggable this entire process becomes.
> Ultimately,
> >> >> > as I
> >> >> > mentioned above, I just do not think it is feasible for ORM and
> OGM to
> >> >> > share all of these implementation contracts.  Forcing a switch from
> >> >> > String
> >> >> > (the DDL) arguments to some amorphic Object reinforces that in my
> >> mind.
> >> >> > But that would not stop OGM from completely swapping
> >> >> > SchemaManagementTool
> >> >> > and its delegates and simply not using Target, Exporters, etc.
> >> >> >
> >> >> >
> >> >> > On Thu, Jan 14, 2016 at 7:44 AM Gunnar Morling <
> gunnar at hibernate.org>
> >> >> > wrote:
> >> >> >
> >> >> >> Hi Steve,
> >> >> >>
> >> >> >> One thing useful to have for OGM would be a generalization of the
> >> >> >> hbm2ddl tooling so we can re-use it for managing NoSQL databases.
> Not
> >> >> >> all of them are "schemaless", e.g. Cassandra works with a fixed
> >> >> >> schema, and while MongoDB largely is schemaless, we still want to
> >> >> >> create stuff like indexes in the database.
> >> >> >>
> >> >> >> I took a look and found that SchemaManagementTool as a pluggable
> >> >> >> service already goes halfway into that direction. The issue with
> it
> >> is
> >> >> >> that I cannot replace the list of exporters used by SchemaExport
> nor
> >> >> >> the list of tool targets used by SchemaUpdate. Having a pluggable
> >> >> >> service allowing me to customize that with an OGM-specific
> >> >> >> implementation should do the trick.
> >> >> >>
> >> >> >> As per some comments in the code, SchemaExport seems to be in some
> >> >> >> intermediary state, where the ops are not executed directly
> through
> >> >> >> the targets passed to SchemaCreator/Dropper but are read into
> String
> >> >> >> arrays which are then passed on to separate exporters. I suppose
> part
> >> >> >> of that work should be to consolidate this and basically follow
> the
> >> >> >> same approach as used in SchemaUpdate?
> >> >> >>
> >> >> >> Another facet is that for some OGM grid dialects we'd need another
> >> >> >> representation of commands than Strings, as not all the backends
> have
> >> >> >> a DDL but expect API invocations for that purpose. For that it'd
> be
> >> >> >> required to change Target#accept(String) into accept(Object) so we
> >> can
> >> >> >> pass some kind of command object. File exports would only work in
> a
> >> >> >> limited fashion, but we could live with that. Schema
> >> creation/dropping
> >> >> >> bound to the SF lifecycle is what I am after here.
> >> >> >>
> >> >> >> I'd be willing to work on this once we agree on the general
> approach.
> >> >> >>
> >> >> >> Any thoughts?
> >> >> >>
> >> >> >> Thanks,
> >> >> >>
> >> >> >> --Gunnar
> >> >> >>
> >> >> >>
> >> >> >>
> >> >> >> 2016-01-13 14:10 GMT+01:00 Guillaume Smet <
> guillaume.smet at gmail.com
> >> >:
> >> >> >> > On Tue, Jan 12, 2016 at 6:40 PM, Steve Ebersole <
> >> steve at hibernate.org>
> >> >> >> wrote:
> >> >> >> >
> >> >> >> >> If you clean up the conflicts I can look for 5.1
> >> >> >> >>
> >> >> >> >
> >> >> >> > Done!
> >> >> >> >
> >> >> >> > --
> >> >> >> > Guillaume
> >> >> >> > _______________________________________________
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> >> >> >>
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