I'm doing maintenance work on a Rails site that I inherited; it's driven by an Oracle database, and I've got access to both development and production installations of the site (each with its own Oracle DB). I'm running into an Oracle error when trying to insert data on the production site, but not the dev site:

ActiveRecord::StatementInvalid (OCIError: ORA-00001: unique constraint (DATABASE_NAME.PK_REGISTRATION_OWNERSHIP) violated: INSERT INTO registration_ownerships (updated_at, company_ownership_id, created_by, updated_by, registration_id, created_at) VALUES ('2006-05-04 16:30:47', 3, NULL, NULL, 2920, '2006-05-04 16:30:47')):
/usr/local/lib/ruby/gems/1.8/gems/activerecord-oracle-adapter-1.0.0.9250/lib/active_record/connection_adapters/oracle_adapter.rb:221:in `execute'
app/controllers/vendors_controller.rb:94:in `create'

As far as I can tell (I'm using Navicat as an Oracle client), the DB schema for the dev site is identical to that of the live site. I'm not an Oracle expert; can anyone shed light on why I'd be getting the error in one installation and not the other?

Incidentally, both dev and production registration_ownerships tables are populated with lots of data, including duplicate entries for country_ownership_id (driven by index PK_REGISTRATION_OWNERSHIP). Please let me know if you need more information to troubleshoot. I'm sorry I haven't given more already, but I just wasn't sure which details would be helpful.