[
Date Prev][
Date Next][
Thread Prev][
Thread Next][
Date Index][
Thread Index]
[
List Home]
|
Re: [dali-dev] Re: schema for JPA connections
|
Hi Tom,
Some comments in-line.
Neil
Tom Mutdosch wrote:
Hi Neil,
I guess the main scenario that I am trying to address is a new user
who wants to add some JPA data to their application. They see the JPA
Generate Entities menu item and run that - they define their
connection, they choose their schema and generate entities. Now they
attempt to run their app but run into two problems:
1) no connection information is set up
2) the wrong schema is being used
However, the user definitively specified both of these things when
they ran through the scenario. So it may be confusing why things
aren't working. I'd like to see some assistance for the user in these
cases.
I agree that this is a usability issue, and perhaps we need to look at
making some changes to Dali to make it more usable out-of-the-box
(without extensions). In the area of vendor properties, this would be a
departure from our current design.
Regarding 1) Since the connection info is a property of a specific
runtime implementation, it is expected that the platform provider is
going to appropriately update the persistence.xml properties with this
information as a part of their Dali extension.
Regarding 2) This depends on what has been configured by the specific
platform, among other things.
I would think that the connection would generally be defined during
project creation, not Entity Generation, but it might be a nice feature
to set the connection for the project during Entity Generation if no
connection is defined yet for the project.
Regarding the schema, what about when generating entities with a
non-default schema, if there was an option to "Make this my default
schema" or something to that affect. This would add the schema to
your orm.xml (and possibly an option to add the schema directly to
your entities via annotation). This would alleviate the problem.
The option could even be off by default, so it would have to be
deliberately enabled. What about something along these lines?
When designated, setting the non-default schema name in the orm.xml
persistence-unit-defaults makes sense to me. Enter an enhancement for
this and I will target it for 2.0. I'm not sure that the annotation
based setting would be as useful, since generally you would only set
schema in the annotations for the occasional table outside of the main
schema (such as a sequence table for example).
As for assisting with the connection, I've brought this up several
times on the list. I'm pretty sure that it's a function of the
platform, but I'm not sure how to best handle this. That is, if the
user selects the OpenJpa platform and defines a connection, can I hook
in somewhere to allow the user to push this connection information to
the persistence.xml (via the provider-specific properties, or a
jta-datasource reference)?
Yes, this is how things are envisioned to work. You can obtain the
connection information from our db plugin and insert the appropriate
properties into the persistence.xml via our persistence unit model.
Ideally, I'd like some way to hook into the Generate Entities wizard
where you select your connection and schema, to provide my own
platform-specific options. Could something like this be set up? It
may be possible to do now, by extending some of the existing Dali
wizards, but that's usually not the preferred way to go. I was trying
to handle this after the Generate Entities operation has run, but
couldn't find a way to get the connection or schema that was used in
that operation. It doesn't look like the selected connection gets set
in project's JPA property page, so I couldn't rely on that property
being set. Is this by design that the user has to explicitly go in
and set this?
We haven't thought about integrating anything into the Generate Entities
wizard. Currently we don't keep any of that information around as you
describe. After some of the enhancements above are implemented, it
would seem possible to obtain this information from the orm.xml and the
project settings.
Thanks
Tom
dali-dev-request@xxxxxxxxxxx wrote:
the way things are going to work at runtime when setting your JDBC
userName in the provider properties. This default is properly
overridden in the orm.xml persistence-unit-defaults, or as specified
by annotation, or as specified in the orm.xml for a given element.
There are a LOT of places to set the schema, depending on the
granularity that you need. This JPA meta data is the where schema
information is stored.
Our validation has to take into account all of these possible schema
settings to determine whether a database object can be resolved for a
given Entity/Mapping. There is no master, all overriding, tool-only
schema setting. We have too many schema settings to keep track of as
it stands. ;) There is a possible argument for having this, but with
so many existing schema settings and defaults, I worry that by
removing confusion on the tooling side with a simple setting, you
might complicate issues when you try to run your application and
don't get the results that you expect.
As for Entity Generation, this does create a bit of an issue when
generating from the non-default schema. I'll carry that conversation
forward in the bug, but it probably needs some discussion to
determine the best course of action.
Neil
_______________________________________________
dali-dev mailing list
dali-dev@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/dali-dev
