Thanks for the quick response Sahoo. Please see inline below...
Sanjeeb Kumar Sahoo wrote:
....
>
> 3. Why are you using MappedSuperclass? Check section #2.1.9 of the JPA
> spec to see if you wanted to use Abstract Entity class instead of
> MappedSuperclass.
I have a restriction that I cannot change the relational schema.
The leaf classes map to the TABLE_PER_CLASS InheritanceType AFAICT.
If I were to make the RegistryObjec and abstract Entity class them the
relational schema requires
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
The InheritanceType.TABLE_PER_CLASS is not supported by Toplink.
Am I correct?
How then do I deal with my problem?
BTW any guess as to when InheritanceType.TABLE_PER_CLASS will be supported?
>
> 4. You are using @ManyToOne in your embeddable class PropertyPK. That's
> not allowed. See section #9.1.35 of the JPA spec.
Sorry but I did not get this one. I need to specify the reverse
relationship in the Property class to the RegistryObject class using the
parent field in the Property class as foreign key to the leaf classes
derived from RegistryObject class somehow. The parent field is defined
in PropertyPK. How do I deal with this issue?
Thanks again for your help.
>
> Sahoo
>
> Farrukh S. Najmi wrote:
>> My apologies in advance for a long email. I have tried to simplify the
>> problem decsription as best as possible and have searched archives and
>> read the spec. Thanks in advance for your help.
>>
>> I am migrating my application from using JDBC to using Java Persistence
>> API. The schema is fixed by an ISO standard (cannot be changed) and
>> represents the relational mapping of an OO model with inheritance
>> semantics.
>>
>> A simplified version of the inheritance Model is shown here:
>>
>> http://ebxmlrr.sourceforge.net/tmp/Simplifiedclassdiagram.png
>>
>> The UML diagram is mapped to the schema such that:
>>
>> -Each leaf class (Oragnization, and Classification) has its own table
>>
>> -There is no table defined for the base class RegistryObject
>>
>> -All base class attributes are duplicated in the leaf class table
>>
>> -A View is defined for the base class RegistryObject which allows for
>> querying at the base class level.
>>
>> -The base class has a collection of composed (Embedded) object Property
>> which uses a composite id and has a foreign key to join with the parent
>> Leaf class (Organization or Classification).
>>
>> -The base class has a collection of composed object (but not embedded
>> from a relational standpoint) Classification which uses a foreign key to
>> join with the parent Leaf class (Organization or Classification).
>>
>> A simplified version schema is as follows:
>>
>> CREATE TABLE Organization (
>> id VARCHAR(256) NOT NULL PRIMARY KEY,
>> ...
>> );
>>
>> CREATE TABLE Classification (
>> id VARCHAR(256) NOT NULL PRIMARY KEY,
>> --Foreign key to parent RegistryObject being classified by this object
>> classifiedObject VARCHAR(256) NOT NULL,
>> ...
>> );
>>
>> CREATE TABLE Property (
>> --Multiple rows of Property make up a single Property to support
>> --collection of values in a single logical Property
>> --The sequenceid is to keep the collection of values ordered
>> sequenceId INT NOT NULL,
>> name_ VARCHAR(256) NOT NULL,
>> value VARCHAR(256),
>> --The parent RegistryObject that this is a Property for
>> parent VARCHAR(256) NOT NULL,
>> PRIMARY KEY (parent, name_, sequenceId)
>> );
>>
>> CREATE VIEW Identifiable (
>> --Base class Attributes
>> id,
>> ...
>> ) AS
>> SELECT
>> id,
>> ...
>> FROM Organization
>> UNION ALL
>> SELECT
>> id,
>> ...
>> FROM Person
>>
>> The Entity classes I have defined for above schema are as follows:
>>
>> @MappedSuperclass
>> public abstract class RegistryObject implements Serializable {
>>
>> @Id
>> @Column(name = "ID", nullable = false)
>> protected String id;
>>
>> @OneToMany (mappedBy="parent", cascade={CascadeType.REMOVE,
>> CascadeType.PERSIST})
>> private Collection<Property> properties;
>>
>> @OneToMany (mappedBy="classifiedObject",
>> cascade={CascadeType.REMOVE, CascadeType.PERSIST})
>> protected Collection<Classification> classifications;
>>
>> ....accessor methods....
>> }
>>
>> @MappedSuperclass
>> public abstract class RegistryObject implements Serializable {
>>
>> @Id
>> @Column(name = "ID", nullable = false)
>> protected String id;
>>
>> @OneToMany (mappedBy="parent", cascade={CascadeType.REMOVE,
>> CascadeType.PERSIST})
>> private Collection<Property> properties;
>>
>> ....accessor methods....
>> }
>>
>> @Entity
>> @Table(name = "SERVICE")
>> public class Organization extends RegistryObject {
>> ...
>> }
>>
>> @Entity
>> @Table(name = "CLASSIFICATION")
>> public class Classification extends RegistryObject {
>> @ManyToOne
>> @JoinColumn(name = "CLASSIFIEDOBJECT", referencedColumnName = "id",
>> table = "RegistryObject", nullable = false)
>> private String classifiedObject;
>>
>>
>> ...
>> }
>>
>> @Entity
>> @Table(name = "PROPERTY")
>> public class Property implements Serializable {
>>
>> @EmbeddedId
>> protected PropertyPK PropertyPK;
>>
>> @Column(name = "VALUE")
>> private String value;
>> ...
>> }
>>
>> @Embeddable
>> public class PropertyPK implements Serializable {
>>
>> @Id
>> @Column(name = "SEQUENCEID", nullable = false)
>> private int sequenceid;
>>
>> @Id
>> @Column(name = "NAME_", nullable = false)
>> private String name;
>>
>> @Id
>> @ManyToOne
>> @JoinColumn(name = "PARENT", referencedColumnName = "id", table =
>> "RegistryObject", nullable = false)
>> private String parent;
>>
>> ...
>> }
...
--
Regards,
Farrukh
Web: http://www.wellfleetsoftware.com
