MappedSuperclass Class
NPersistence Reference Guide
Designates a class whose mapping information is applied to the entities that inherit from it.

A mapped superclass has no separate table defined for it.

A class designated with the MappedSuperclass annotation can be mapped in the same way as an entity except that the mappings will apply only to its subclasses since no table exists for the mapped superclass itself.

When applied to the subclasses the inherited mappings will apply in the context of the subclass tables. Mapping information may be overridden in such subclasses by using the AttributeOverride and AssociationOverride annotations or corresponding XML elements.

Examples

CopyC#
Example: Concrete class as a mapped superclass

[MappedSuperclass]
public class Employee {

    [Id] protected Integer empId;
    [Version] protected Integer version;
    [ManyToOne] [JoinColumn(name="ADDR")]
    protected Address address;

    public Integer getEmpId() { ... }
    public void setEmpId(Integer id) { ... }
    public Address getAddress() { ... }
    public void setAddress(Address addr) { ... }
}

// Default table is FTEMPLOYEE table
[Entity]
public class FTEmployee extends Employee {

    // Inherited empId field mapped to FTEMPLOYEE.EMPID
    // Inherited version field mapped to FTEMPLOYEE.VERSION
    // Inherited address field mapped to FTEMPLOYEE.ADDR fk

    // Defaults to FTEMPLOYEE.SALARY
    protected Integer salary;

    public FTEmployee() {}

    public Integer getSalary() { ... }

    public void setSalary(Integer salary) { ... }
}

[Entity] [Table(name="PT_EMP")]
[AssociationOverride(Name="address")]
[JoinColumn(AttributeRef="address",Name="ADDR_ID")]
public class PartTimeEmployee extends Employee {

    // Inherited empId field mapped to PT_EMP.EMPID
    // Inherited version field mapped to PT_EMP.VERSION
    // address field mapping overridden to PT_EMP.ADDR_ID fk
    [Column(name="WAGE")]
    protected Float hourlyWage;

    public PartTimeEmployee() {}

    public Float getHourlyWage() { ... }
    public void setHourlyWage(Float wage) { ... }
}

Namespace: NPersistence
Assembly: NPersistence (in NPersistence.dll) Version: 2.0.0.0 (2.0.0.0)

Syntax

   
 C# 
public sealed class MappedSuperclass : Attribute

Members

      
 All Members  Constructors  
 Public

 Protected
 Instance

 Static 
 Declared

 Inherited
 XNA Framework Only 

 .NET Compact Framework Only 

 MemberDescription
MappedSuperclass()()()()
Initializes a new instance of the MappedSuperclass class

Inheritance Hierarchy

System..::..Object
  System..::..Attribute
    NPersistence..::..MappedSuperclass

See Also