[Hibernate-issues] [Hibernate-JIRA] Commented: (ANN-120) Map, OneToMany, join table or @ManyToMany does not work

[Noel B. (JIRA) <no...@at...>]

    [ http://opensource.atlassian.com/projects/hibernate/browse/ANN-120?page=comments#action_21822 ] 

Noel Bush commented on ANN-120:
-------------------------------

I'm hoping I can come up with a simple patch -- Hibernate and the Annotations project are pretty complex, but I believe I see the place where this formula is generated.

But I am really curious about your point of view that this isn't important. You've mentioned that before, and perhaps I am just misunderstanding something, but I cannot understand how it would not seem *essential* that Hibernate (with or without Annotations) should be able to persist members of a class that are Maps, just like any other member of a class. You don't think that Maps themselves are inessential, do you? If I adopt the position that Maps are not important because they don't match up neatly with a relational model, then I am basically saying that I have to re-work my application to work only in terms that are "friendly" to relational concepts. And this seems to be in the wrong direction, purpose-wise, from what ORM tools are supposed to be.

But I say all this out of naivete, without a solid background in relational modeling. I admit that I'm one of the people looking for something that "just works", rather than requiring me to become a database expert.

In any case, I will try my (limited) best to come up with a patch that deals with this issue, and will see if it is actually usable in the grander scheme of all things Hibernate.

> Map, OneToMany, join table or @ManyToMany does not work
> -------------------------------------------------------
>
>          Key: ANN-120
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/ANN-120
>      Project: Hibernate Annotations
>         Type: Bug

>   Components: binder
>     Versions: 3.1beta6
>  Environment: Hibernate 3.1 RC1, Annotations 3.1b6, Java 1.5.0_05
>     Reporter: Mattias Arbin
>  Attachments: KeyValue.java, MyEntity.java, TestKeyValue.java
>
>
> Seems like there is a problem with mapping a Map using join table. 
> I have a relation like this:
> @OneToMany(cascade=CascadeType.ALL)
>     @MapKey(name="name")
>     public Map<String, KeyValue> getProps() {
>         return props;
>     }
> The correct tables are created and inserting data works fine. When loading, however, I get the error below.
> When using a join column, everything works fine:
> @OneToMany(cascade=CascadeType.ALL)
>     @MapKey(name="name")
>     @JoinColumn(name="myentity_id")
>     public Map<String, KeyValue> getProps() {
>         return props;
>     }
> Attached the two test classes.
> The error:
> ...
> Hibernate: select this_.id as id3_0_ from test_MyEntity this_
> Hibernate: select props0_.MyEntity_id as MyEntity1_1_, props0_.props_id as props2_1_, props0_.name as formula0_1_, keyvalue1_.id as id2_0_, keyvalue1_.val as val2_0_, keyvalue1_.name as name2_0_ from test_MyEntity_KeyValue props0_ left outer join test_KeyValue keyvalue1_ on props0_.props_id=keyvalue1_.id where props0_.MyEntity_id=?
> 15:11:49,078  WARN JDBCExceptionReporter:71 - SQL Error: 1054, SQLState: 42S22
> Exception in thread "main" 15:11:49,078 ERROR JDBCExceptionReporter:72 - null,  message from server: "Unknown column 'props0_.name' in 'field list'"
> org.hibernate.exception.SQLGrammarException: could not initialize a collection: [test.data.MyEntity.props#1]
> 	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:65)
> 	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
> 	at org.hibernate.loader.Loader.loadCollection(Loader.java:1923)
> 	at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:71)
> 	at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:520)
> 	at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
> 	at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1565)
> 	at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
> 	at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
> 	at org.hibernate.collection.AbstractPersistentCollection.readElementByIndex(AbstractPersistentCollection.java:161)
> 	at org.hibernate.collection.PersistentMap.get(PersistentMap.java:127)
> 	at test.TestKeyValue.test(TestKeyValue.java:43)
> 	at test.TestKeyValue.main(TestKeyValue.java:57)
> Caused by: java.sql.SQLException: null,  message from server: "Unknown column 'props0_.name' in 'field list'"
> 	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1876)
> 	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1098)
> 	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1192)
> 	at com.mysql.jdbc.Connection.execSQL(Connection.java:2051)
> 	at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1496)
> 	at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:137)
> 	at org.hibernate.loader.Loader.getResultSet(Loader.java:1676)
> 	at org.hibernate.loader.Loader.doQuery(Loader.java:662)
> 	at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:223)
> 	at org.hibernate.loader.Loader.loadCollection(Loader.java:1916)
> 	... 10 more

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