Class ForeignKeyRIChecker

java.lang.Object

org.apache.derby.impl.sql.execute.GenericRIChecker

org.apache.derby.impl.sql.execute.ForeignKeyRIChecker

public class ForeignKeyRIChecker
extends GenericRIChecker

A Referential Integrity checker for a foreign key constraint. It makes sure the foreign key is intact. This is used for a change to a foreign key column. see ReferencedKeyRIChecker for the code that validates changes to referenced keys.

Field Summary

Fields inherited from class GenericRIChecker

deferredRowsHashTable, fkDcocis, fkInfo, fkScocis, identityMap, indexQualifierRow, lcc, numColumns, refDcoci, refScoci, tc

Constructor Summary

Constructors

Constructor	Description
ForeignKeyRIChecker(LanguageConnectionContext lcc, TransactionController tc, FKInfo fkinfo)

Method Summary

Modifier and Type	Method	Description
(package private) void	doCheck(Activation a, ExecRow row, boolean restrictCheckOnly, int deferredRowReq)	Check that the row either has a null column(s), or corresponds to a row in the referenced key.
(package private) int	getRICheckIsolationLevel()	Get the isolation level for the scan for the RI check.

Methods inherited from class GenericRIChecker

close, getScanController, isAnyFieldNull

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ForeignKeyRIChecker

ForeignKeyRIChecker(LanguageConnectionContext lcc,
 TransactionController tc,
 FKInfo fkinfo)
             throws StandardException

Parameters:

lcc - the language connection context

tc - the xact controller

fkinfo - the foreign key information

Throws:

StandardException - Thrown on failure

Method Details

doCheck

void doCheck(Activation a,
 ExecRow row,
 boolean restrictCheckOnly,
 int deferredRowReq)
      throws StandardException

Check that the row either has a null column(s), or corresponds to a row in the referenced key.

If the referenced key is found, then it is locked when this method returns. The lock is held until the next call to doCheck() or close().

Specified by:

doCheck in class GenericRIChecker

Parameters:

a - the activation

row - the row to check

restrictCheckOnly - true if the check is relevant only for RESTRICTED referential action.

deferredRowReq - dummy (interface obligation only)

Throws:

StandardException - on unexpected error, or on a foreign key violation

getRICheckIsolationLevel

int getRICheckIsolationLevel()

Get the isolation level for the scan for the RI check. NOTE: The level will eventually be instantaneous locking once the implementation changes.

Overrides:

getRICheckIsolationLevel in class GenericRIChecker

Returns:

The isolation level for the scan for the RI check.