Package jakarta.persistence

Annotation Type DiscriminatorColumn

  • @Target(TYPE)
@Retention(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:
    1.0
    See Also:
    DiscriminatorValue

    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element Description
      String columnDefinition
      (Optional) The SQL fragment that is used when generating the DDL for the discriminator column.
      DiscriminatorType discriminatorType
      (Optional) The type of object/column to use as a class discriminator.
      int length
      (Optional) The column length for String-based discriminator types.
      String name
      (Optional) The name of column to be used for the discriminator.

    • Element Detail

      • name

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

      • discriminatorType

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

      • columnDefinition

        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

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