i need to define two attributes of a class to point to the same <component>.




not surprisingly this causes causes :
[STDERR] net.sf.hibernate.MappingException: Repeated column in mapping for class com.alterpoint.aof.objects.platform.impl.ManagedElementImpl should be mapped with insert="false" update="false": firstName

any solutions for this (or is it a usage issue..)

thanks
ravi

tell us what do exactly want to do ?
is there an association between name and mother?
you want to do Employee.getName().getFirstName()

AND Employee.getMotherName().getFirstName()

both representing exactly the data? (row/column)
or is there a link on the same table?

this should make it more obvious. the employee class looks like this

essentially there will be a set of fields (3) in the database for each of the name attributes. so both attribute DONOT represent the same columns in the database.

yes, i do want to be able to do

which returns two different name objects.

thnx

can you give employees table details?

i think you need two many to one (one for name, one for mother), not two components...

it's not that complicated.

if you look at the manual under section 18.1 my example is just an extension to it.


all i'm trying to do is add another field to the employee class as described above. so there's no scope for a many to one association.

thnx

The error is telling you that you have two properties mapped to the same column. This is occurring because the default mapping of a Property to a column is to use the proprty name as the column name (http://www.hibernate.org/hib_docs/reference/html_single/#or-mapping-s1-7). So you need to specify a column name for the Properties in either your component mapping for name="name" or name="motherName".

Your table "employees" has to have seperate fields for the Employee's firstname and the Mother's firstname to use a component.

HTH

Mike

yes, i agree that the source of the problem is obviously the conflicting property names (which are also the column names).

i was looking for a more hands-off solution, since i generate the xmls from tags as below:



and the Name



the generated xml is what i had posted earlier. there is no way to tell the generator to change the property name="firstName" if it is referred to twice in the same class. a workaround for this is what i'm looking for, the last resort being hand-editing the generated mapping xml

i guess i steered the question partly into the XDoclet lane.

thanks

in fact the columns are not the same aren't they?

but the problem may be generation from xdoclet as you said.

I had another limitation about xdoclet, we can try to add patchs... but in your case it looks it's going to be hard :-/

The solution is to add a new tag option


so your example could then become
[code]
Employee {

To different instances of the same component class - that's what you mean ?

By default Hibernate will use the property name for the column - causing the clash in your example... Why don't you just override this default behavior by specifing the column name yourself ?


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that's all well and good, and in fact exactly how i was doing it, but xdoclet does not allow such flexibility

my suggestion was an enhancement to the xdoclet tags, not hibernate per se

Misunderstood your question then - sorry about that.

just an update for the code-gen enthusiasts.

i attempted to find a solution to this problem today afternoon and i'm very close to completing the .xdt to create unique fieldnames based on an extra attribute specified with the component tag.

the challenge so far has been that we want to specify the tag on the @hibernate.compoent tag BUT want it to manifest itself in the .property tag. i had to look at the programmatic power of the xdoclet template language so it took a little longer than i thought.

stay tuned

having done some tweaks to the .xdt i got my solution working but then also found an existing fix that i decided to stick to.

you can implement the fix at the the Xdoclet JIRA for this same issue
http://opensource.atlassian.com/projects/xdoclet/browse/XDT-733

there's an improvement to the solution suggested which you can easily implement yourself.

enjoy
ravi

Thanks for the fix, Ravi. I'm using Xdoclet 1.2.1, but I am not getting the behavior descrbed with 'prefix'. I examined the .xdt and java source and see that the fix as described in Jira has been implemented in this version.

I've boiled it down to a simple example of a Person entity with two Address components, one for 'home' and one for 'billing' to illustrate.

Adding a 'prefix' attribute to the @hibernate.component tag does not result in a prefixed column attribute for the component's properties.

Can anyone confirm that XDoclet 1.2.1 accurately implements the 'prefix' additon to @hibernate.component ?

Here are the relevant snippets of the xdoclet tags and resulting mapping:




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