Hello,

I'm new to Hibernate. I'm using Middlegen to create my .hbm.xml files from an existing database but when I feed these files into hbm2java it does generate the .java files but complains about the XML when doing so;

[hbm2java] (hbm2java.CodeGenerator 48 ) Error parsing XML: file:/C:/eclipse/workspace/Stakez-Hibernate/build/gen-src/stakez/hibernate/Stakezuser.hbm.xml(19)
[hbm2java] org.xml.sax.SAXParseException: Element "class" does not allow "property" here.
[hbm2java] at org.apache.crimson.parser.Parser2.error(Parser2.java:3210)
.........
.........

Where am I going wrong? Is the xml generated by Middlegen correct? am I missing somthing when I call hbm2java?


many thanks

James




The hbm.xml files generated from Middlegen are;

Xchangelog.hbm.xml & Stakezuser.hbm.xml

-----------------------

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping>

<!--
Created by Middlegen Hibernate plugin

http://boss.bekk.no/boss/middlegen/
http://hibernate.sourceforge.net/
-->

<class
name="stakez.hibernate.Xchangelog"
table="xchangelog"
>
<property
name="username"
type="java.lang.String"
column="username"
length="20"
/>
<property
name="ipaddress"
type="java.lang.String"
column="ipaddress"
length="15"
/>
<property
name="sentdate"
type="java.sql.Date"
column="sentdate"
length="4"
/>

<!-- associations -->

</class>
</hibernate-mapping>



---------------------


<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping>

<!--
Created by Middlegen Hibernate plugin

http://boss.bekk.no/boss/middlegen/
http://hibernate.sourceforge.net/
-->

<class
name="stakez.hibernate.Stakezuser"
table="stakezuser"
>
<property
name="username"
type="java.lang.String"
column="username"
not-null="true"
length="20"
/>
<property
name="password"
type="java.lang.String"
column="password"
not-null="true"
length="20"
/>
<property
name="email"
type="java.lang.String"
column="email"
not-null="true"
length="60"
/>
<property
name="level"
type="java.lang.String"
column="level"
length="10"
/>
<property
name="url"
type="java.lang.String"
column="url"
length="80"
/>
<property
name="sent"
type="int"
column="sent"
length="4"
/>
<property
name="recieved"
type="int"
column="recieved"
length="4"
/>
<property
name="status"
type="java.lang.String"
column="status"
length="10"
/>
<property
name="owed"
type="int"
column="owed"
length="4"
/>

<!-- associations -->

</class>
</hibernate-mapping>



I call hbm2java from ant;

<target name="hbm2java"
description="Generate .java from .hbm files.">

<taskdef
name="hbm2java"
classname="net.sf.hibernate.tool.hbm2java.Hbm2JavaTask"
classpathref="lib.class.path"
/>

<hbm2java output="${build.java.dir}" classpathref="lib.class.path">
<fileset dir="${build.gen-src.dir}">
<include name="**/*.hbm.xml"/>
</fileset>
</hbm2java>
</target>

It looks as though your id field is not being generated correctly.bbAre your tables using composite primary ids that are made up of two or more foreign keys? If so, this is a bug in middlegen.

-Kat

Ah well that would explain why the first db I tried didn't work.

Thanks for pointing me in the right direction.

James

I have finished adding support in the middlgen for this. I will release it after testing and finishing further enhancement I have been working on.

Actually - How about sending me the database schema for this just to make sure it is coverred. david@hibernate.org

have the same problem David.

See topic "Middlegen generates hbm xml without ids?" for example DDL.

-Joe

Already fixed it and it is getting closer to a release. The weekend I expect.

Cool! My boss will be pleased.. he has been breathing down my neck on this.

-K

Are composite primary ids made up of foreign keys considered bad form for Hibernate? I've heard Surrogate keys are prefered. Why ?

I'm using Middlegen to generate stuff from an existing DB, but I can redesign things if need be.

What's people opinion on this?

I've wondered the exact same thing.

Part of me worries that my object model is suffering from tunnel-vision because of my database schema.

I don't have links to pass on but compound keys are not the best database design. Just use synthetic keys and keep away from business knowledge based keys. It will bite you otherwise. The other side is that its so much nicer dealing with the objects, database and mappings with synthetic keys as compound keys just add complexity for no (or negative) benefit.

We shouldnt use composite keys even in the *database*??

I figured that was always right on the DB level, and Hibernate abstracted that for us into the object model.

While we're on the subject, what's wrong with this? I keep getting told key-property tags have to have class defined, and mine do.

[/code]

If you are designing a new database or new tables. You should use synthetic keys if at all possible. You will avoid many issues as the schema (and data requirements) change.

The compound key - key-property does not have class on it. Name yes but not class. Maybe you were thinking of key-many-to-one. Anyway, here is an example:

BTW: Middlegen r3 has been released.