public interface ForeignMultiKeyNullifier
A key nullifier is used with a secondary database that is configured to
have a foreign key integrity constraint and a delete action of ForeignKeyDeleteAction.NULLIFY
. The key nullifier is specified by calling
SecondaryConfig.setForeignMultiKeyNullifier(com.sleepycat.je.ForeignMultiKeyNullifier)
.
When a referenced record in the foreign key database is deleted and the
foreign key delete action is NULLIFY
, the nullifyForeignKey(com.sleepycat.je.SecondaryDatabase, com.sleepycat.je.DatabaseEntry, com.sleepycat.je.DatabaseEntry, com.sleepycat.je.DatabaseEntry)
method is called. This method
sets the foreign key reference to null in the datum of the primary
database. The primary database is then updated to contain the modified
datum. The result is that the secondary key is deleted.
SecondaryKeyCreator
or SecondaryMultiKeyCreator
for many-to-many, one-to-many, many-to-one and
one-to-one relationships.Modifier and Type | Method and Description |
---|---|
boolean |
nullifyForeignKey(SecondaryDatabase secondary,
DatabaseEntry key,
DatabaseEntry data,
DatabaseEntry secKey)
Sets the foreign key reference to null in the datum of the primary
database.
|
boolean nullifyForeignKey(SecondaryDatabase secondary, DatabaseEntry key, DatabaseEntry data, DatabaseEntry secKey) throws DatabaseException
secondary
- the database in which the foreign key integrity
constraint is defined. This parameter is passed for informational
purposes but is not commonly used.key
- the existing primary key. This parameter is passed for
informational purposes but is not commonly used.data
- the existing primary datum in which the foreign key
reference should be set to null. This parameter should be updated by
this method if it returns true.secKey
- the secondary key to be nullified. This parameter is
needed for knowing which key to nullify when multiple keys are present,
as when SecondaryMultiKeyCreator
is used.DatabaseException
- if an error occurs attempting to clear the key
reference.Copyright (c) 2002, 2017 Oracle and/or its affiliates. All rights reserved.