It's actually a bit easier for me to describe the database schema than
the api, so I'll start with that;
I'd like a primary entity table to store all "fixed" fields for the
entity, along with primary key. Any "dynamic" entity fields would
generate separate tables which might look like:
Table name: <name of entity>_<name of field>
Column 1: foreign key to entity table
Column 2: field value
Column 2 type: defined in terms of field type
(indices defined as needed)
Of course, if the dynamic field type were something more complex than a
basic type, then this organization would have to be extended somehow..
Andy
Patrick Linskey wrote:
Can you describe what you're looking for in more detail, both in terms
of the database schema and the Java APIs?
-Patrick
On Tue, Feb 26, 2008 at 9:44 AM, Andy Schlaikjer <[EMAIL PROTECTED]> wrote:
On a somewhat related note, I'm interested in using column stores for
entities with arbitrary, typed attributes, but not sure how I might
structure this in JPA. Any thoughts?
Andy
Patrick Linskey wrote:
> Hi,
>
> In Java SE, this is trivial: simply do not list persistent types,
> jars, or mapping files in your persistence.xml file. Dynamic class
> loading is discussed in the docs [1].
>
> It would be nice to add an API to register new classes even when other
> types are listed in persistence.xml; the underlying capability exists,
> but the product does not have such an explicit API.
>
> -Patrick
>
> [1]
http://openjpa.apache.org/docs/latest/manual/ref_guide_pc.html#ref_guide_pc_pcclasses
>
> On Sun, Feb 24, 2008 at 2:10 AM, cws <[EMAIL PROTECTED]> wrote:
>> brief: I want to add an unknown entity to my running PU in JavaSE.
>>
>> My JavaSE client app needs to load new, unknown entities (classes, not
>> objects) from a trusted URLClassLoader. I would like to add these new
>> entities to the existing PU, but this doesn't seem possible in SE
>> without changing the persistence.xml and restarting. As a kludge I can
>> send a persistence.xml with the class and create a new PU, but that
>> doesn't allow interaction with unknown entities in the existing PU.
>>
>> I believe the spec requires all classes to be known at start, but I'm
>> hoping OpenJPA or something else has implemented this dynamic
>> feature(?). Are there any established workarounds for the client here?
