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
When a referenced record in the foreign key database is deleted and the
foreign key delete action is
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.
SecondaryMultiKeyCreatorfor many-to-many, one-to-many, many-to-one and one-to-one relationships.
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
DatabaseException- if an error occurs attempting to clear the key reference.
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