Package org.eclipse.persistence.annotations

Enum BatchFetchType

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description
      EXISTS
      This uses an SQL EXISTS and a sub-select in the batch query instead of a join.
      IN
      This uses an SQL IN clause in the batch query passing in the source object Ids.
      JOIN
      This is the default form of batch reading.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static BatchFetchType valueOf​(java.lang.String name)
      Returns the enum constant of this type with the specified name.
      static BatchFetchType[] values()
      Returns an array containing the constants of this enum type, in the order they are declared.

      • Methods inherited from class java.lang.Enum

        clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

      • Methods inherited from class java.lang.Object

        getClass, notify, notifyAll, wait, wait, wait

    • Enum Constant Detail

      • JOIN

        public static final BatchFetchType JOIN
        This is the default form of batch reading. The original query's selection criteria is joined with the batch query.

      • EXISTS

        public static final BatchFetchType EXISTS
        This uses an SQL EXISTS and a sub-select in the batch query instead of a join. This has the advantage of not requiring an SQL DISTINCT which can have issues with LOBs, or may be more efficient for some types of queries or on some databases.

      • IN

        public static final BatchFetchType IN
        This uses an SQL IN clause in the batch query passing in the source object Ids. This has the advantage of only selecting the objects not already contained in the cache, and can work better with cursors, or if joins cannot be used. This may only work for singleton Ids on some databases.

    • Method Detail

      • values

        public static BatchFetchType[] values()
        Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows: 
        for (BatchFetchType c : BatchFetchType.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static BatchFetchType valueOf​(java.lang.String name)
        Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
        Parameters:
        name - the name of the enum constant to be returned.
        Returns:
        the enum constant with the specified name
        Throws:
        java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
        java.lang.NullPointerException - if the argument is null