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Posted to dev@openjpa.apache.org by jeff <je...@yahoo.com> on 2007/03/16 18:43:58 UTC
schema generation, OpenJPA vs. Toplink
i'm new here, so please excuse if this is a stupid question ...
from my cursory look at OpenJPA, it seems that it takes a different approach to schema generation than TopLink.
Toplink generates a schema from annotations, where OpenJPA requires one to provide a DB-neutral XML schema file. do i have that right?
i am trying to understand the advantages of OpenJPA's approach. from my naive standpoint right now, it seems less than optimal. if the metadata is already captured in annotations, why require it to be defined in the schema XML file?
am i missing something?
thanks.
---------------------------------
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RE: schema generation, OpenJPA vs. Toplink
Posted by Patrick Linskey <pl...@bea.com>.
Jeff,
Just to clarify, OpenJPA does support directly creating a DDL file or
altering a schema from the information that you provide in annotations.
-Patrick
--
Patrick Linskey
BEA Systems, Inc.
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> -----Original Message-----
> From: Marc Prud'hommeaux [mailto:mprudhomapache@gmail.com] On
> Behalf Of Marc Prud'hommeaux
> Sent: Friday, March 16, 2007 10:48 AM
> To: open-jpa-dev@incubator.apache.org
> Subject: Re: schema generation, OpenJPA vs. Toplink
>
> Jeff-
>
> OpenJPA provides the ability to generate a schema to an intermediate
> XML file, but it doesn't require it. You can also create the schema
> directly against the database.
>
> Using the intermediate XML file can be useful if you want to
> generate
> the schema, but then make additional modifications to it
> (like adding
> indexes) before actually building the schema against the
> database. It
> can also be useful to capture the schema locally, since OpenJPA can
> be configured to validate mappings against the schema file rather
> than validating it against database metadata (which can sometimes be
> slow).
>
> For example scenarios for using the mappingtool, see:
>
> http://incubator.apache.org/openjpa/docs/latest/manual/
> manual.html#ref_guide_mapping_mappingtool_examples
>
>
>
> On Mar 16, 2007, at 10:43 AM, jeff wrote:
>
> > i'm new here, so please excuse if this is a stupid question ...
> >
> > from my cursory look at OpenJPA, it seems that it takes a
> different
> > approach to schema generation than TopLink.
> >
> > Toplink generates a schema from annotations, where OpenJPA
> requires
> > one to provide a DB-neutral XML schema file. do i have that right?
> >
> > i am trying to understand the advantages of OpenJPA's approach.
> > from my naive standpoint right now, it seems less than optimal. if
> > the metadata is already captured in annotations, why require it to
> > be defined in the schema XML file?
> >
> > am i missing something?
> > thanks.
> >
> >
> >
> >
> > ---------------------------------
> > Expecting? Get great news right away with email Auto-Check.
> > Try the Yahoo! Mail Beta.
>
>
Re: schema generation, OpenJPA vs. Toplink
Posted by Marc Prud'hommeaux <mp...@apache.org>.
Jeff-
OpenJPA provides the ability to generate a schema to an intermediate
XML file, but it doesn't require it. You can also create the schema
directly against the database.
Using the intermediate XML file can be useful if you want to generate
the schema, but then make additional modifications to it (like adding
indexes) before actually building the schema against the database. It
can also be useful to capture the schema locally, since OpenJPA can
be configured to validate mappings against the schema file rather
than validating it against database metadata (which can sometimes be
slow).
For example scenarios for using the mappingtool, see:
http://incubator.apache.org/openjpa/docs/latest/manual/
manual.html#ref_guide_mapping_mappingtool_examples
On Mar 16, 2007, at 10:43 AM, jeff wrote:
> i'm new here, so please excuse if this is a stupid question ...
>
> from my cursory look at OpenJPA, it seems that it takes a different
> approach to schema generation than TopLink.
>
> Toplink generates a schema from annotations, where OpenJPA requires
> one to provide a DB-neutral XML schema file. do i have that right?
>
> i am trying to understand the advantages of OpenJPA's approach.
> from my naive standpoint right now, it seems less than optimal. if
> the metadata is already captured in annotations, why require it to
> be defined in the schema XML file?
>
> am i missing something?
> thanks.
>
>
>
>
> ---------------------------------
> Expecting? Get great news right away with email Auto-Check.
> Try the Yahoo! Mail Beta.