[hibernate-issues] [Hibernate-JIRA] Issue Comment Edited: (HHH-5176) property-ref doesn't work when property is inside join tags of destination mapping

[Stephen Visser (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-5176?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=36791#action_36791 ] 

Stephen Visser edited comment on HHH-5176 at 4/29/10 3:30 PM:
--------------------------------------------------------------

>From my understanding the 'column' attribute refers to the column of the local table that identifies the many-to-one relationship.  'property-ref' is used to specify the foreign-key of the destination table when we are joining on a column other than the primary key.  The result that I'm looking for in this particular many-to-one relationship is something like:


SELECT ...

FROM COURSE_ENROLMENTS c
JOIN STUDENTS s
    ON *s.STUDENT_ID=c.STUDENT_ID*
JOIN PERSONS p
    ON s.PERSON_ID=p.PERSON_ID


The c.STUDENT_ID is specified by the 'column' attribute, and the s.STUDENT_ID is _SUPPOSED_ to be specified by the 'property-ref' attribute.  The property-ref works, but instead of using the alias 's' in the above example, STUDENT_ID is prefixed by 'p'.  I can only assume that this is because in my original mapping, the <join> tags aren't taken into account.


      was (Author: sgv):
    From my understanding the 'column' attribute refers to the column of the local table that identifies the many-to-one relationship.  'property-ref' is used to specify the foreign-key of the destination table when we are joining on a column other than the primary key.  The result that I'm looking for in this particular many-to-one relationship is something like:

{quote}
SELECT ...

FROM COURSE_ENROLMENTS c
JOIN STUDENTS s
    ON *s.STUDENT_ID=c.STUDENT_ID*
JOIN PERSONS p
    ON s.PERSON_ID=p.PERSON_ID
{quote}

The c.STUDENT_ID is specified by the 'column' attribute, and the s.STUDENT_ID is _SUPPOSED_ to be specified by the 'property-ref' attribute.  The property-ref works, but instead of using the alias 's' in the above example, STUDENT_ID is prefixed by 'p'.  I can only assume that this is because in my original mapping, the <join> tags aren't taken into account.

  
> property-ref doesn't work when property is inside join tags of destination mapping
> ----------------------------------------------------------------------------------
>
>                 Key: HHH-5176
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5176
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.5.0-Final
>         Environment: mapping
>            Reporter: Stephen Visser
>
> My legacy system requires that I have a join in the mappings to fully specify.
> Here is the mapping of the entity.
> {quote}
> <hibernate-mapping>         
>     <class name="Student" table="PERSONS" lazy="false">
>         <id name="personID" column="PERSON_ID"/>
>         <property name="lastName" column="LEGAL_SURNAME" />
>         <property name="firstName" column="LEGAL_FIRST_NAME" />
>         <property name="birthDate" column="DATE_OF_BIRTH" />
>         
>         <join table="STUDENTS">
>             <key column="PERSON_ID"/>
>             <property name="studentID" column="STUDENT_ID" unique="true" />
>         </join>   
>     </class>
> </hibernate-mapping>
> {quote}
> However, when I reference the entity in another mapping:
> {code}
> <hibernate-mapping>
>     <class name="Enrolment" table="COURSE_ENROLLMENTS" lazy="false">
>         <id name="enrolmentID" column="course_enrollment_id" />
>         <many-to-one name="student" column="student_id" class="Student" lazy="false"  property-ref="studentID"/>
>     </class>
> </hibernate-mapping>
> {code}
> The studentID property in the Student mapping is assumed to be in the PERSONS table (when in fact it is in the STUDENTS table since it's inside the join tags).  This results in the alias of the PERSONS table being prepended to the STUDENT_ID column.
> When using the property-ref attribute, it should be determined if the referenced property is inside any join tags.  If it is, the correct table alias should be inferred.

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