On Thu, Sep 03, 2009 at 07:24:50AM -0700, Richard Broersma wrote: > On Wed, Sep 2, 2009 at 4:35 PM, David Fetter<david@xxxxxxxxxx> wrote: > > > Hibernate has the very nice feature of being able to get out of > > your way. Properly used, it can keep completely out of the > > business of making (wrong) guesses based on DDL, which is what > > ORMs often do. DBIx::Class > > <http://search.cpan.org/dist/DBIx-Class/> has gone a long way in > > the right direction. > > > > Ones which (attempt to) dictate decisions about DDL are just off > > the map. :P > > David, do you know how well these kinds of ORMs work when it come to > mapping non-trivial schema designs? For example, how would these > work when creating a mapping for the multiple inheritance design > that you've blogged about earlier? If your mapper only does the job of mapping, you can choose classes/objects and then map them to the appropriate, possibly parameterized, SQL queries, which the DB people can then freely rearrange. One nice feature of such a system is that the DBA and/or DB developer has a way to know what the client code expects. In OO terms, there are public interfaces--everything mentioned in the ORM layer--and private interfaces--DDL, DML, and DCL--to the database. Programmers who like to use object-oriented languages and methods should be happy about this object-oriented approach to database management, but for some reason, a lot of them don't understand that the idea of public and private interfaces applies to what they (too simplistically, much of the time) think of as "the persistence layer." Cheers, David. -- David Fetter <david@xxxxxxxxxx> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@xxxxxxxxx Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
