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Inheritance and polymorphic associations

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Jhc

Post subject: Inheritance and polymorphic associations

Posted: Sat Jan 08, 2005 3:29 pm

Newbie

Joined: Sat Jan 08, 2005 2:23 pm
Posts: 3

Hello,

here the specifications of the problem:

Hibernate version: hibernate-2.1.7c

Name of the database you are using: PointBase

* Class hierarchy:

- Java code:

Abstract class: abstract class SyntaxTreeComponent
Abstract class: abstract class Rule extends SyntaxTreeComponent
Concrete class: class ConditionalRule extends Rule
Abstract class: abstract class Operation extends SyntaxTreeComponent
Concrete class: class ComparisonOp extends Operation

- Graphical representation ('<-' = inherits):

Code:

 
(abstract) SyntaxTreeComponent <-  (abstract) Rule <- ConditionalRule
                               <-  (abstract) Operation <-  ComparisonOp

* Polymorphic association:

A conditional rule has an (abstract) operation.

* Mapping files:

Used the 'table per subclass' strategy (reason: polymofism).

- SyntaxTreeComponent.hbm.xml:

Code:

<hibernate-mapping>    
   <class 
       name="SyntaxTreeComponent" 
       table="SYNTAX_TREE_COMPONENT">
       <id
          name="id"
          column="SYNTAX_COMPONENT_ID"
          type="long">
          <generator class="native"/>
       </id>                                                                         
   </class> 
</hibernate-mapping>

- Operation.hbm.xml (Operation+ComparisonOp):

Code:

    
<hibernate-mapping>
   <joined-subclass 
       name="Operation" 
       extends="SyntaxTreeComponent" 
       table="OPERATION">
       <key column="OPERATION_ID"/>
       <joined-subclass 
            name="ComparisonOp" 
            table="COMPARISON_OP">
           <key column="COMPARISON_OP_ID"/>
       </joined-subclass>
   </joined-subclass>
</hibernate-mapping>

- Rule.hbm.xml (Rule+ConditionRule) CONTAINS THE PROBLEM ASSOCIATION:

Code:

    
<hibernate-mapping> 
   <joined-subclass
        name="Rule"
        extends="SyntaxTreeComponent"
        table="RULE">
        <key column="RULE_ID"/>
        <joined-subclass
            name="ConditionalRule"
            table="CONDITIONAL_RULE">
            <key column="CONDITIONAL_RULE_ID"/>
            <many-to-one 
                 name="operation" 
                 class="Operation" 
                 column="OPERATION_ID" 
                 cascade="save-update"/>
         </joined-subclass>
    </joined-subclass> 
</hibernate-mapping>

* Error messages:

Code:

Code:

 
   Rule rule = new ConditionalRule(new ComparisonOp());  
    ...
   session.save(rule);
    ...
 

Error:

Code:

JDBCExceptionReporter:58 - Referential Integrity Violation. CONDITIONAL_RULE references OPERATION
...
Caused by: java.sql.SQLException: Referential Integrity Violation. CONDITIONAL_RULE references OPERATION

Thanks in advance,
Johan

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Jhc

Post subject:

Posted: Sat Jan 08, 2005 4:22 pm

Newbie

Joined: Sat Jan 08, 2005 2:23 pm
Posts: 3

Here some extra information about the SQL statements:

Code:

create table SYNTAX_TREE_COMPONENT (
   SYNTAX_COMPONENT_ID bigint not null,
   primary key (SYNTAX_COMPONENT_ID)
)
create table CONDITIONAL_RULE (
   CONDITIONAL_RULE_ID bigint not null,
   OPERATION_ID bigint,
   primary key (CONDITIONAL_RULE_ID)
)
create table RULE (
   RULE_ID bigint not null,
   primary key (RULE_ID)
)
create table COMPARISON_OP (
   COMPARISON_OP_ID bigint not null,
   primary key (COMPARISON_OP_ID)
)
create table OPERATION (
   OPERATION_ID bigint not null,
   primary key (OPERATION_ID)
)
create table FIELD (
   FIELD_ID bigint not null,
   primary key (FIELD_ID)
)

Is it possible that there is a problem with primary/foreign keys?

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Jhc

Post subject:

Posted: Sun Jan 09, 2005 9:33 pm

Newbie

Joined: Sat Jan 08, 2005 2:23 pm
Posts: 3

Problem solved...

By accident declared my id as long in place of Long.

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