javax.persistence

Annotation Type DiscriminatorColumn

Contents

  • @Target(value=TYPE)
 @Retention(value=RUNTIME)
public @interface DiscriminatorColumn
    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 { ... }
    Since:
    Java Persistence 1.0
    See Also:
    DiscriminatorValue

    • Element Detail

      • name

        public abstract String name
        (Optional) The name of column to be used for the discriminator.
        Default:
        "DTYPE"

      • discriminatorType

        public abstract DiscriminatorType discriminatorType
        (Optional) The type of object/column to use as a class discriminator. Defaults to DiscriminatorType.STRING.
        Default:
        javax.persistence.DiscriminatorType.STRING

      • columnDefinition

        public abstract String columnDefinition
        (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.

        Default:
        ""

      • length

        public abstract int length
        (Optional) The column length for String-based discriminator types. Ignored for other discriminator types.
        Default:
        31

Document created the 11/06/2005, last modified the 18/08/2025
Source of the printed document:https://www.gaudry.be/en/java-api-javaee-rf-javax/persistence/DiscriminatorColumn.html

The infobrol is a personal site whose content is my sole responsibility. The text is available under CreativeCommons license (BY-NC-SA). More info on the terms of use and the author.

References

  1. View the html document Language of the document:fr Manuel PHP : https://docs.oracle.com, DiscriminatorColumn (Java(TM) EE 7 Specification APIs)

These references and links indicate documents consulted during the writing of this page, or which may provide additional information, but the authors of these sources can not be held responsible for the content of this page.
The author of this site is solely responsible for the way in which the various concepts, and the freedoms that are taken with the reference works, are presented here. Remember that you must cross multiple source information to reduce the risk of errors.