inverse relationships generated by hbm2java

d · **Joined:** Mon Jul 04, 2005 5:19 pm **Posts:** 720

Hibernate version:
hibernate3.jar & hibernate-tools.jar from JBossIDE-N200509280156-ALL

part of Waterbdy.hbm.xml

Code:

        <set name="sites" inverse="true">
            <key>
                <column name="llid_no" length="13" not-null="true" />
            </key>
            <one-to-many class="Site" />
        </set>

Generated domain models are behaving differently regarding the value of the attribute known as ejb3 ;-)

For the above mapping, note that Site (the many side) is the relationship owner . If I deploy this all is well. However, if I leave out the mapping document, and set the attribute known as ejb3 to true, here is the generated java ...

Code:

   @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
   @JoinColumn(name = "llid_no")
   public Set<gov.blm.ak.arims.generated.Site> getSites() {
      return this.sites;
   }

This relationship behaves much differently - taking transient Waterbdy instances into a persistent state w/ an update tries to delete all related Sites - whereas the mapping document instructs H to ignore this. This is fixed if I manually make the following change to the @OneToMany annotation:

Code:

@OneToMany(mappedBy="site", cascade = CascadeType.ALL, fetch = FetchType.LAZY)

1.) Is it correct to say that mappedBy="site" for @OneToMany is analogous to inverse="true" in the set element in the hbm.xml ? I say this because the following is in the dox.

Code:

To declare a side as not responsible for the relationship, the attribute mappedBy is used

2.) If so, shouldn't the tool generate 'mappedBy' if inverse="true" ?

3.) Can someone please reconcile these two discrepencies in the documentation?

Code:

The rules you have to remember are straightforward: All bi-directional associations need one side as inverse. In a one-to-many association it has to be the many-side

Code:

Since many to one are (almost) always the owner side of a bidirectional relationship

why the almost? how the almost?

d · **Joined:** Mon Jul 04, 2005 5:19 pm **Posts:** 720

also, I realize this stuff isn't relased yet, but it appears unique= false for all of the @Id properties .

max · **Posted:** Sat Oct 01, 2005 2:06 am

hi,

please remember that the hbm2java ejb3 generator is under heavy development thus it will not cover all siyuations from day one ;)

that said its good to get information about which features are missing, but those i would really prefer to have in jira instead of here.

regarding appedby/inverse then your assumptions are mostly correct - mappedby and inverse are in practice the exact same thing and normally they are equilavent in the way you describe.

the issue is just that mappeby explicitly points to the "other" side where as inverse does not - so inverse does not rquire another side. it is more a hint and hibernate actually doesnt care what the other side is and thus their might not be an "other" side.

And thus hbm2java must make assumptions and guess what the the other side is exactly...and that is not always possible.

We are actually considering adding mappedby to the DTD just to allow the tools to be stronger (but the core doesnt care)

d · **Joined:** Mon Jul 04, 2005 5:19 pm **Posts:** 720

I will try to be a little less hesitant about jira from now on. it's just that there are so many issue trackers in OS w/ a poor signal to noise ratio.

Your point about the subtle differences of @inverse and mappedBy is something I had not thought of.

max · **Posted:** Sat Oct 01, 2005 3:36 am

yes and we also do have our share of signal to noise ratio.

But now where we have something in active development and you are so nice to poke to it and discover areas that is not yet covered I would like it to go to jira so we can track it...when it gets to much i'll say that too...but for now - put obvious missing features/bugs regarding the tools into the jira.

bsdwork · **Joined:** Thu Sep 27, 2007 10:48 am **Posts:** 5

I was never hesitant about jira.. I had no reason.. it has so many features and i got along with it just great until now.. but who knows..

Features

* Manage bugs, features, tasks, improvements or any issue
* A clean and powerful user interface that is easy to understand for both business and technical users
* Map your business processes to custom workflows
* Track attachments, changes, components and versions
* Full text searching and powerful filtering (customisable, saveable, shareable and subscribeable!)
* Customisable dashboards and real-time statistics
* Enterprise permissioning and security
* Easily extended to and integrated with other systems (including email, RSS, Excel, XML and source control)
* Highly configurable notification options
* Runs on almost any hardware, OS and database platform
* Web service enabled for programmatic control (SOAP, XML-RPC and REST interfaces)

_________________
“Change the changeable, accept the unchangeable, and remove yourself from the unacceptable.” ~ Denis Waitley
[url=http://www.tryforsalebyowner.com/tips_for_selling.html
]fsbo home selling tip[/url]