MarshalledTupleKeyEntity (Oracle - Berkeley DB Java API)
Date: 2010-04-12

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## com.sleepycat.bind.tuple
Interface MarshalledTupleKeyEntity

    public interface MarshalledTupleKeyEntity

A marshalling interface implemented by entity classes that represent keys as tuples. Since `MarshalledTupleKeyEntity` objects are instantiated using Java deserialization, no particular constructor is required by classes that implement this interface.

Note that a marshalled tuple key extractor is somewhat less efficient than a non-marshalled key tuple extractor because more conversions are needed. A marshalled key extractor must convert the entry to an object in order to extract the key fields, while an unmarshalled key extractor does not.

See Also:
  `TupleTupleMarshalledBinding`, `TupleSerialMarshalledBinding`

Method Summary
`void` | `marshalPrimaryKey(TupleOutput keyOutput)` Extracts the entity's primary key and writes it to the key output.
`boolean` | `marshalSecondaryKey(String keyName, TupleOutput keyOutput)` Extracts the entity's secondary key and writes it to the key output.
`boolean` | `nullifyForeignKey(String keyName)` Clears the entity's secondary key fields for the given key name.
`void` | `unmarshalPrimaryKey(TupleInput keyInput)` Completes construction of the entity by setting its primary key from the stored primary key.

Method Detail

### marshalPrimaryKey

    void marshalPrimaryKey(TupleOutput keyOutput)

  Extracts the entity's primary key and writes it to the key output.

  Parameters:
    `keyOutput` - is the output tuple.

### unmarshalPrimaryKey

    void unmarshalPrimaryKey(TupleInput keyInput)

  Completes construction of the entity by setting its primary key from the stored primary key.

  Parameters:
    `keyInput` - is the input tuple.

### marshalSecondaryKey

    boolean marshalSecondaryKey(String keyName,
                                TupleOutput keyOutput)

  Extracts the entity's secondary key and writes it to the key output.

  Parameters:
    `keyName` - identifies the secondary key.
    `keyOutput` - is the output tuple.
  Returns:
    true if a key was created, or false to indicate that the key is not present.

### nullifyForeignKey

    boolean nullifyForeignKey(String keyName)

  Clears the entity's secondary key fields for the given key name.

  The specified index key should be changed by this method such that `marshalSecondaryKey(java.lang.String, com.sleepycat.bind.tuple.TupleOutput)` for the same key name will return false. Other fields in the data object should remain unchanged.

  If `ForeignKeyDeleteAction.NULLIFY` was specified when opening the secondary database, this method is called when the entity for this foreign key is deleted. If NULLIFY was not specified, this method will not be called and may always return false.

  Parameters:
    `keyName` - identifies the secondary key.
  Returns:
    true if the key was cleared, or false to indicate that the key is not present and no change is necessary.

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