Hi Mathias, I think we might need to see more of your model to understand what is going on. In the query you gave:
SELECT t0.ID, t0.DESCRIPTION, t0.NAME, t0.TYPE, t1.PATH, t2.PASSWORD, t3.VALUE FROM ELEMENT t0 JOIN FILE t1 ON (t0.ID = t1.ID) JOIN PRINCIPAL t2 ON (t0.ID = t2.ID) JOIN PERMISSION t3 ON (t0.ID = t3.ID) I'm curious as to while FILE is listed there when you are retrieving PRINCIPAL. I suspect you have something in the joins not quite right. Another option would be to do a smaller test case. Create a small project with just the inheritance and use an H2 in-memory database to test it. This is how I often explore a lot of things. H2 is great for this kind of activity because it is small and vast and you don't need a complicated setup (it is memory-only). If you try this, be sure you use org.apache.cayenne.access.dbsync.CreateIfNoSchemaStrategy on the DataNode to automatically create your schema for your test. mrg On Tue, Dec 13, 2011 at 2:47 AM, Mathias Clerc <tlarhi...@gmail.com> wrote: > 2011/12/13 Mathias Clerc <tlarhi...@gmail.com>: >> Hi Michael, >> >> Hello >> >> Actually I am trying to use Cayenne vertical inheritance. Some more >> details on what I did : >> >> I have followed the guide here : >> http://cayenne.apache.org/doc30/modeling-vertical-inheritance.html >> and with a lot of trial and error, I finally got it to insert data. >> >> Unfortunately I cannot make the select queries to work correctly. >> After some searches I found that old thread with the same problem : >> http://cayenne.195.n3.nabble.com/Vertical-inheritance-td827636i20.html >> I tried the workaround from that thread but it didn't help. >> >> >> In my DB, I have one root table called ELEMENT from which the tables >> "FILE", "PRINCIPAL" and "PERMISSION" are inheriting. >> If I create a new ELEMENT like this : >> Element elem = context.newObject(Element.class); >> elem.setName("test1"); >> elem.setDescription("test1 description"); >> elem.setType("ELEMENT"); >> Or a PRINCIPAL like this : >> Principal p = context.newObject(Principal.class); >> p.setPassword("password"); >> p.setName("principal1"); >> p.setDescription("principal1 description"); >> p.setType("PRINCIPAL"); >> It inserts perfectly. >> >> If I then run through JDBC "SELECT t0.ID, t0.DESCRIPTION, t0.NAME FROM >> ELEMENT t0", I get the values back. >> >> But if I make a simple select with Cayenne like : >> context.performQuery(new SelectQuery(Element.class)); >> >> It does not return anything as it is trying to use the query : >> SELECT t0.ID, t0.DESCRIPTION, t0.NAME, t0.TYPE, t1.PATH, t2.PASSWORD, >> t3.VALUE FROM ELEMENT t0 JOIN FILE t1 ON (t0.ID = t1.ID) JOIN >> PRINCIPAL t2 ON (t0.ID = t2.ID) JOIN PERMISSION t3 ON (t0.ID = t3.ID) >> >> The query is wrong as it is trying to join the parent table on all the >> child tables at the same time. >> "test1" is in no subtable and "principal1" is not in FILE or PERMISSION. >> >> I have put the map file content there : http://pastebin.com/KtVhDdYE >> >> >> Do you have any idea on what to try next to get it to work ? >> >> 2011/12/13 Michael Gentry <mgen...@masslight.net>: >>> Hi Mathias, >>> >>> I believe you are trying to use a currently unimplemented inheritance >>> mechanism. Cayenne does not currently support horizontal >>> (multiple-table) inheritance: >>> >>> http://cayenne.apache.org/doc/inheritance-overview.html >>> >>> There are tricks you can do to make working with multiple related >>> tables easier (such as adding getters/setters in your subclass to >>> reference the parent), but you cannot currently model this behavior >>> automatically. >>> >>> mrg >>> >>> >>> On Fri, Dec 9, 2011 at 3:00 AM, Mathias Clerc <tlarhi...@gmail.com> wrote: >>>> Hello, >>>> >>>> It seems like I have missed something in inheritance in Cayenne. >>>> >>>> I have one main table called "Element" with fields id (PK), name and >>>> description >>>> Another table "File" inherits from "Element" with fields ID(PK, FK on >>>> Element.id) and path. >>>> >>>> When I do a context.performIteratedQuery(new >>>> SelectQuery(Element.class)) The query I see is : >>>> SELECT t0.ID, t0.DESCRIPTION, t0.NAME, t0.TYPE, t0.ID, t0.ID, t0.PATH >>>> FROM ELEMENT t0 >>>> >>>> I tried checking and unchecking the "To Dep PK" field for the relation in >>>> ID. >>>> >>>> What did I miss ? > > If I replace my query by : > String sql = "select * FROM ELEMENT"; > SQLTemplate select = new SQLTemplate(Element.class, sql); > > List<?> result = context.performQuery(select); > > Then it works perfectly well. When an element with type="FILE" is > found it returns a File instance, when an element with > type="PRINCIPAL" is found it returns a Principal instance. > > I guess I am missing some simple checkbox somewhere in the modeler.
