[hibernate-dev] [ORM/OGM] String-typed version properties

[Gunnar Morling]

After discussing the matter with Steve, I've created
https://hibernate.atlassian.net/browse/HHH-8757 for this and will create a
PR for the change.


2013/11/26 Gunnar Morling <gunnar at hibernate.org>

> Thoughts, anyone? Steve?
>
> Thanks,
>
> --Gunnar
>
>
>
> 2013/11/21 Gunnar Morling <gunnar at hibernate.org>
>
>> All,
>>
>> I'm working on supporting on the CouchDB backend for OGM, and more
>> specifically on integrating the optimistic locking functionality which is
>> built into CouchDB [1].
>>
>> For that purpose, each CouchDB document has a defined field "_rev" which
>> is a UUID and is updated on the server-side upon each write. So I thought I
>> could map this attribute like this:
>>
>>      @Generated //this prop. needs to be read back value after writes
>>     @Version //this prop. is used for optimistic locking
>>     String _rev;
>>
>> But this gave me a CCE since @Version is not allowed on Strings
>> (org.hibernate.type.StringType is no VersionType).
>>
>> Looking around, I found BinaryType which looks like what'd I need for
>> Strings, there is also a note mentioning basically the same use case case
>> [2]. If I register a custom type derived from StringType with an equivalent
>> implementation of the VersionType contract, I get the behavior I need.
>>
>> Does anyone see a problem with making o.h.t.String a VersionType in this
>> way (i.e. it'd only support DB-generated values)?
>>
>> Thanks,
>>
>> --Gunnar
>>
>> [1] https://hibernate.atlassian.net/browse/OGM-392
>> [2] "only known application of binary types for versioning is for use
>> with the TIMESTAMP datatype supported by Sybase and SQL Server, which are
>> completely db-generated values"
>>
>>
>