> Cayenne and EOF use a similar method, i.e. a table for the primary keys, but > there’s an implementation difference — EOF stores the *last* primary key > value provided while Cayenne stores the *next* value to be used. This means > they can’t share a single table (by using a view for the naming differences). > > Anyone have any brilliant ideas or workarounds for this? (before I start > messing around with triggers or other messy workarounds).
Cayenne has PkGenerator interface that can be customized/reimplemented: http://cayenne.apache.org/docs/4.0/api/org/apache/cayenne/dba/PkGenerator.html Unfortunately it is not directly injectable via DI (this is a TODO), so initializing it will require a bit of indirection. E.g. you may subclass of decorate DbAdapterFactory. Here is a decoration example: new ServerRuntimeBuilder() .addModule(binder -> binder .decorate(DbAdapterFactory.class) .after(MyDbAdapterFactory.class)).build(); public class MyDbAdapterFactory implements DbAdapterFactory { private DbAdapterFactory delegate; public MyDbAdapterFactory(@Inject DbAdapterFactory delegate) { this.delegate = delegate; } @Override public DbAdapter createAdapter(DataNodeDescriptor nodeDescriptor, DataSource dataSource) throws Exception { DbAdapter a = deletegate.createAdapter(nodeDescriptor, dataSource); return .. // here decorate "a" to return a custom PkGenerator. } } > On the subject of PK generation, there’s one thing I really like in EOF; if > the PK table is missing a row for a table, EOF will automatically select the > max() value of the table's PK column and use it to populate the table. Quite > useful. Any objections to this becoming a feature in Cayenne as well? (via > pull request) I am all +1 on this. I'd say PK generation has been neglected for some time, so we should freshen it up, including auto-bootstrap that you mentioned, and DI integration, maybe smarter categorization by generator strategy, etc. One of the reasons I personally haven't payed much attention to this lately, is cause I am using DB autoincrement (something not supported by EOF) and never had to worry about PK lookup tables, sequences, etc. :) Andrus > On May 22, 2015, at 1:33 PM, Hugi Thordarson <h...@karlmenn.is> wrote: > > Hi again. > > I’m using EOF and Cayenne to talk to the same MySQL database. Works fine > apart from one problem: Primary key generation. > > Cayenne and EOF use a similar method, i.e. a table for the primary keys, but > there’s an implementation difference — EOF stores the *last* primary key > value provided while Cayenne stores the *next* value to be used. This means > they can’t share a single table (by using a view for the naming differences). > > Anyone have any brilliant ideas or workarounds for this? (before I start > messing around with triggers or other messy workarounds). > > On the subject of PK generation, there’s one thing I really like in EOF; if > the PK table is missing a row for a table, EOF will automatically select the > max() value of the table's PK column and use it to populate the table. Quite > useful. Any objections to this becoming a feature in Cayenne as well? (via > pull request) > > Cheers, > - hugi > > PS: Sorry for spamming the list with my stupid questions these days: > hopefully I’ll be able to contribute in a meaningful way soon, rather than > just sucking at the teat of your knowledge :). > > // Hugi Thordarson > // http://www.loftfar.is/ <http://www.loftfar.is/> > // s. 895-6688
