@UniqueConstraint involving associated entities

jtorin · **Joined:** Thu Sep 28, 2006 5:16 am **Posts:** 1

I'm using JBoss (4.0.4.GA-Patch1) and EJB3 and have found a small inconvinence. Searching the forums reveals similar problems, but I'm unable to see if they are related or even the same thing.

I have one entity bean ("ConsentDecision") reference another ("Sample") through a many-to-one relation. I want to put a unique constraint on ConsentDecision to make sure they are unique in relation to one Sample (I'm not using the real id-field of ConsentDecision but that is unrelated).

So, I add:
@Entity

Code:

@Table(uniqueConstraints =
    { @UniqueConstraint(columnNames = { "storeId", "sample" }) })
public class ConsentDecision implements java.io.Serializable { ... }

to my bean, and this wont work since the field "sample" is defined as:

Code:

@ManyToOne
public Sample getSample() { ... }

This generates an exception:

Quote:

org.hibernate.MappingException: Unable to find column with logical name: ConsentDecision.sample

However, if alter the definition of the relation slighly:

Code:

@ManyToOne
@JoinColumn(name = "sample_pseudosampleid")
public Sample getSample() { ...}

and then the entity definition:

Code:

@Entity
@Table(uniqueConstraints =
    { @UniqueConstraint(columnNames = { "storeId", "sample_pseudosampleid" }) })
public class ConsentDecision implements java.io.Serializable { ...}

This works fine, generating the following SQL (Postgres):

Quote:

...
CONSTRAINT consentdecision_storeid_key UNIQUE (storeid, sample_pseudosampleid)
...

So, my question is: shouldn't it be possible to derive the name from the association field, just like an ordinary field? The name "sample_pseudosampleid" is what is generated by Hibernate on ordinary deployment and should be available somewhere, somehow.

Anyway, hope this helps someone else.

emmanuel · **Posted:** Thu Sep 28, 2006 11:45 am

no I'm against that.
you are playing with 2 different notions, properties and columns. No mix and match

joaodelvalle · **Joined:** Wed Nov 29, 2006 9:17 am **Posts:** 1

Emmanuel, but why is it possible with attributes and not with associations? It seems a bit awkward to me that you have to code like:

Code:

// a state name is unique in the country
@Entity
@Table(uniqueConstraints =
  {@UniqueConstraint(
    columnNames = { "state_Country", "stateName" })})
public class State {

   private Long id;

   private String stateName;

   private Country stateCountry;

...
}

That seems more like mixing concepts. This was tested to work with Hibernate 3.2.1 and ImprovedNamingStrategy. But it does not work if I change the names to:

Code:

columnNames = { "stateCountry", "stateName" }

AFAIU, these were supposed to be the logical names, right? Am I missing something?

Thanks,
João.

emmanuel · **Posted:** Mon Dec 04, 2006 5:04 pm

Now this one is a bug, please create a JIRA issue