Thanks for your reply, Lukas! See comments below: On Wednesday, September 3, 2014 7:37:15 AM UTC-7, Lukas Eder wrote: > > Hello Josh, > > 2014-09-02 21:18 GMT+02:00 Josh Padnick <[email protected] <javascript:> > >: > >> Hello, >> >> First, been really enjoying jOOQ. What a pleasure to use and have the >> full power of SQL available. Ok, so my question is about modeling >> inheritance with jOOQ. >> >> I've reviewed the history of posts on this and come across: >> >> - https://groups.google.com/d/msg/jooq-user/9dfbLtnR77c/_0GL1H7f2ZYJ >> - https://groups.google.com/d/msg/jooq-user/FLrkH_u2bbE/zJS8DQeFu2wJ >> - https://groups.google.com/d/msg/jooq-user/9X_0gROVIf8/XZc2OXqitJQJ >> - https://groups.google.com/d/msg/jooq-user/YuTp9-5K9fs/_d5siyYQn3EJ >> >> I understand (and agree) with Lukas's position that since SQL does not >> directly model inheritance, jOOQ should not either. I'd like to describe >> my approach to working around this and would appreciate any feedback for >> better ways of handling this. >> > > Hmm, that's not 100% my position. SQL (or at least ORDBMS like Oracle and > PostgreSQL) does support inheritance. So far, this kind of true ORDBMS > table inheritance has been a low priority for jOOQ, though, as it is hardly > ever used. > > As far as various models of mapping Java inheritance to SQL through > discriminators, joins, etc. is concerned, I'm indeed a bit reluctant as > jOOQ does not implement this kind of ORM. >
Thanks for clarifying. I would say that jOOQ's support of inheritance works great for us, with the exception of the limitation imposed by java's lack of support for multiple inheritance. > > >> *SQL* >> We have the following tables: >> >> CREATE TABLE notify_event ( >> notify_event_id SERIAL NOT NULL, >> PRIMARY KEY (notify_event_id), >> ); >> >> >> CREATE TABLE notify_event_text_message ( >> notify_event_id INTEGER NOT NULL, >> message_body TEXT NOT NULL, >> CONSTRAINT PK_notify_event_text_message PRIMARY KEY (notify_event_id) >> ); >> >> Basically, a notify_event is the parent type, and >> notify_event_text_message is the subtype. >> >> *Object Model* >> In Java, we have modeled this as follows: >> >> - class NotifyEvent extends generated.tables.pojos.NotifyEvent >> - class NotifyEventTextMessage extends NotifyEvent >> >> We're using a POJO pattern where we define our own POJOs, but just extend >> from the jOOQ auto-generated POJO in most cases and then add in any >> customizations we want. This has worked very nicely so far, particularly >> for converting to/from JSON with the opportunity to customize the JSON >> serialization. >> >> It even works well with patterns like: >> >> notifyEventTextMessageRecord.into( models.NotifyEventTextMessage.class ) >> >> And then I manually manage the POJO member property links. >> >> *My Questions* >> Does anyone else use this pattern with success? Are there unforeseen >> issues we may run into down the line? >> >> So far, it's worked very well, with the sole exception that we have to >> copy & paste the jOOQ auto-generated POJO into any subtypes (e.g. >> NotifyEventTextMessage above) because Java doesn't like multiple >> inheritance. >> > > You might be able to implement that copy & pasting also when overriding > the code generator behaviour... Have you tried that? > I have not, and hadn't considered that! So, I guess I would explicitly declare child tables somewhere and then auto-generate the corresponding POJOs. The only issue with this is that we then manually customize these POJOs using the Jackson library to facilitate automatic conversion to JSON. That's nothing more than adding annotations, though, so I could probably handle that as well. Looks like the best docs for this are at http://www.jooq.org/doc/3.4/manual/code-generation/codegen-generatorstrategy/. > > Apart from that, given that you're using PostgreSQL, you may in fact try > to use PostgreSQL's inheritance mechanism. This will be transparent to > jOOQ, and jOOQ will generate NotifyEventTextMessage POJOs with all > inherited columns as well. > I had considered this, but was a little freaked out about the limitations outlined at http://www.postgresql.org/docs/9.3/static/ddl-inherit.html. It seemed like we were trading one problem (the inherent mismatch between Java inheritance and SQL) for another problem (the particular quirks Postgres inheritance has for constraints). Do you know of anyone successfully using this in production? Did they find it to be worth the overhead? Thanks as always for your prompt and insightful responses. > > More information here: > http://www.postgresql.org/docs/9.3/static/tutorial-inheritance.html > > Cheers > Lukas > -- You received this message because you are subscribed to the Google Groups "jOOQ User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
