JPA Annotation

DiscriminatorColumn

Target: TYPE
Implemented Interfaces:
Annotation
Specifies the discriminator column for the SINGLE_TABLE and JOINED Inheritance mapping strategies.

The strategy and the discriminator column are only specified in the root of an entity class hierarchy or subhierarchy in which a different inheritance strategy is applied

If the DiscriminatorColumn annotation is missing, and a discriminator column is required, the name of the discriminator column defaults to "DTYPE" and the discriminator type to DiscriminatorType.STRING. 

Example:
     @Entity
     @Table(name="CUST")
     @Inheritance(strategy=SINGLE_TABLE)
     @DiscriminatorColumn(name="DISC", discriminatorType=STRING, length=20)
     public class Customer { ... }

     @Entity
     public class ValuedCustomer extends Customer { ... }
 
See Also:
DiscriminatorValue
Since:
JPA 1.0
Public Annotation Attributes
String columnDefinition default ""
 (Optional) The SQL fragment that is used when generating the DDL for the discriminator column.
 
 Defaults to the provider-generated SQL to create a column of the specified discriminator type. 
Since:
JPA 1.0
DiscriminatorType discriminatorType default STRING
 (Optional) The type of object/column to use as a class discriminator.
 Defaults to DiscriminatorType.STRING. 
Since:
JPA 1.0
int length default 31
 (Optional) The column length for String-based discriminator types.
 Ignored for other discriminator types. 
Since:
JPA 1.0
String name default "DTYPE"
 (Optional) The name of column to be used for the discriminator.
 
Since:
JPA 1.0