com.sleepycat.je
Class SecondaryDatabase

java.lang.Object
  com.sleepycat.je.Database
      com.sleepycat.je.SecondaryDatabase

All Implemented Interfaces:

Closeable

public class SecondaryDatabase
extends Database

A secondary database handle.

Secondary databases are opened with Environment.openSecondaryDatabase and are always associated with a single primary database. The distinguishing characteristics of a secondary database are:

• Records are automatically added to a secondary database when records are added, modified and deleted in the primary database. Direct calls to put() methods on a secondary database are prohibited.
• The delete method of a secondary database will delete the primary record and as well as all its associated secondary records.
• Calls to all get() methods will return the data from the associated primary database.
• Additional get() method signatures are provided to return the primary key in an additional pKey parameter.
• Calls to openCursor will return a SecondaryCursor, which itself has get() methods that return the data of the primary database and additional get() method signatures for returning the primary key.

Before opening or creating a secondary database you must implement the SecondaryKeyCreator or SecondaryMultiKeyCreator interface.

For example, to create a secondary database that supports duplicates:

     Database primaryDb; // The primary database must already be open.
     SecondaryKeyCreator keyCreator; // Your key creator implementation.
     SecondaryConfig secConfig = new SecondaryConfig();
     secConfig.setAllowCreate(true);
     secConfig.setSortedDuplicates(true);
     secConfig.setKeyCreator(keyCreator);
     SecondaryDatabase newDb = env.openSecondaryDatabase(transaction,
                                                         "myDatabaseName",
                                                         primaryDb,
                                                         secConfig)
 

If a primary database is to be associated with one or more secondary databases, it may not be configured for duplicates.

WARNING: The associations between primary and secondary databases are not stored persistently. Whenever a primary database is opened for write access by the application, the appropriate associated secondary databases should also be opened by the application. This is necessary to ensure data integrity when changes are made to the primary database. If the secondary database is not opened, it will not be updated when the primary is updated, and the references between the databases will become invalid. (Note that this warning does not apply when using the DPL, which does store secondary relationships persistently.)

Special considerations for using Secondary Databases with and without Transactions

Normally, during a primary database write operation (insert, update or delete), all associated secondary databases are also updated. However, when an exception occurs during the write operation, the updates may be incomplete. If the databases are transactional, this is handled by aborting the transaction to undo the incomplete operation. If an auto-commit transaction is used (null is passed for the transaction), the transaction will be aborted automatically. If an explicit transaction is used, it must be aborted by the application caller after the exception is caught.

However, if the databases are non-transactional, integrity problems can result when an exception occurs during the write operation. Because the write operation is not made atomic by a transaction, references between the databases will become invalid if the operation is incomplete. This results in a SecondaryIntegrityException when attempting to access the databases later.

A secondary integrity problem is persistent; it cannot be resolved by reopening the databases or the environment. The only way to resolve the problem is to restore the environment from a valid backup, or, if the integrity of the primary database is assumed, to remove and recreate all secondary databases.

Therefore, secondary databases and indexes should always be used in conjunction with transactional databases and stores. Without transactions, it is the responsibility of the application to handle the results of the incomplete write operation or to take steps to prevent this situation from happening in the first place.

The following exceptions may be thrown during a write operation, and may cause an integrity problem in the absence of transactions.

• SecondaryConstraintException, see its subclasses for more information.
• LockConflictException, when more than one thread is accessing the databases.
• EnvironmentFailureException, if an unexpected or system failure occurs.
• There is always the possibility of an Error or an unintended RuntimeException.

Field Summary

Fields inherited from class com.sleepycat.je.Database

logger

Method Summary

void	close() Closes a secondary database and dis-associates it from its primary database.
OperationStatus	delete(Transaction txn, DatabaseEntry key) Deletes the primary key/data pair associated with the specified secondary key.
OperationStatus	get(Transaction txn, DatabaseEntry key, DatabaseEntry pKey, DatabaseEntry data, LockMode lockMode) Retrieves the key/data pair with the given key.
OperationStatus	get(Transaction txn, DatabaseEntry key, DatabaseEntry data, LockMode lockMode) Retrieves the key/data pair with the given key.
SecondaryConfig	getConfig() Returns a copy of the secondary configuration of this database.
Database	getPrimaryDatabase() Returns the primary database associated with this secondary database.
SecondaryConfig	getPrivateSecondaryConfig() Returns the secondary config without cloning, for internal use.
OperationStatus	getSearchBoth(Transaction txn, DatabaseEntry key, DatabaseEntry pKey, DatabaseEntry data, LockMode lockMode) Retrieves the key/data pair with the specified secondary and primary key, that is, both the primary and secondary key items must match.
OperationStatus	getSearchBoth(Transaction txn, DatabaseEntry key, DatabaseEntry data, LockMode lockMode) This operation is not allowed with this method signature.
SecondaryConfig	getSecondaryConfig() Deprecated. As of JE 4.0.13, replaced by getConfig().
JoinCursor	join(Cursor[] cursors, JoinConfig config) This operation is not allowed on a secondary database.
SecondaryCursor	openCursor(Transaction txn, CursorConfig cursorConfig) Obtain a cursor on a database, returning a SecondaryCursor.
SecondaryCursor	openSecondaryCursor(Transaction txn, CursorConfig cursorConfig) Deprecated. As of JE 4.0.13, replaced by openCursor(com.sleepycat.je.Transaction, com.sleepycat.je.CursorConfig).
OperationStatus	put(Transaction txn, DatabaseEntry key, DatabaseEntry data) This operation is not allowed on a secondary database.
OperationStatus	putNoDupData(Transaction txn, DatabaseEntry key, DatabaseEntry data) This operation is not allowed on a secondary database.
OperationStatus	putNoOverwrite(Transaction txn, DatabaseEntry key, DatabaseEntry data) This operation is not allowed on a secondary database.

Methods inherited from class com.sleepycat.je.Database

compareDuplicates, compareKeys, count, getDatabaseName, getEnvironment, getSecondaryDatabases, getStats, openCursor, openSequence, preload, preload, preload, removeSequence, sync, verify

Methods inherited from class java.lang.Object

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

Method Detail

close

public void close()
           throws DatabaseException

Closes a secondary database and dis-associates it from its primary database. A secondary database should be closed before closing its associated primary database. Discards the database handle.

When closing the last open handle for a deferred-write database, any cached database information is flushed to disk as if Database.sync() were called.

The database handle should not be closed while any other handle that refers to it is not yet closed; for example, database handles should not be closed while cursor handles into the database remain open, or transactions that include operations on the database have not yet been committed or aborted. Specifically, this includes Cursor and Transaction handles.

When multiple threads are using the Database handle concurrently, only a single thread may call this method.

When called on a database that is the primary database for a secondary index, the primary database should be closed only after all secondary indices which reference it have been closed.

The database handle may not be accessed again after this method is called, regardless of the method's success or failure.

WARNING: To guard against memory leaks, the application should discard all references to the closed handle. While BDB makes an effort to discard references from closed objects to the allocated memory for an environment, this behavior is not guaranteed. The safe course of action for an application is to discard all references to closed BDB objects.

Specified by:

close in interface Closeable

Overrides:

close in class Database

Throws:

DatabaseException

See Also:

DatabaseConfig.setDeferredWrite

getPrimaryDatabase

public Database getPrimaryDatabase()

Returns the primary database associated with this secondary database.

Returns:

the primary database associated with this secondary database.

getSecondaryConfig

public SecondaryConfig getSecondaryConfig()
                                   throws DatabaseException

Deprecated. As of JE 4.0.13, replaced by getConfig().

Returns a copy of the secondary configuration of this database.

Returns:

a copy of the secondary configuration of this database.

Throws:

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

DatabaseException

getConfig

public SecondaryConfig getConfig()
                          throws DatabaseException

Returns a copy of the secondary configuration of this database.

Overrides:

getConfig in class Database

Returns:

a copy of the secondary configuration of this database.

Throws:

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

DatabaseException

getPrivateSecondaryConfig

public SecondaryConfig getPrivateSecondaryConfig()

Returns the secondary config without cloning, for internal use.

openSecondaryCursor

public SecondaryCursor openSecondaryCursor(Transaction txn,
                                           CursorConfig cursorConfig)
                                    throws DatabaseException

Deprecated. As of JE 4.0.13, replaced by openCursor(com.sleepycat.je.Transaction, com.sleepycat.je.CursorConfig).

Obtain a cursor on a database, returning a SecondaryCursor. Calling this method is the equivalent of calling openCursor(com.sleepycat.je.Transaction, com.sleepycat.je.CursorConfig) and casting the result to SecondaryCursor.

Parameters:

txn - the transaction used to protect all operations performed with the cursor, or null if the operations should not be transaction protected. If the database is non-transactional, null must be specified. For a transactional database, the transaction is optional for read-only access and required for read-write access.

cursorConfig - The cursor attributes. If null, default attributes are used.

Returns:

A secondary database cursor.

Throws:

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

DatabaseException

openCursor

public SecondaryCursor openCursor(Transaction txn,
                                  CursorConfig cursorConfig)
                           throws DatabaseException

Obtain a cursor on a database, returning a SecondaryCursor.

Overrides:

openCursor in class Database

Parameters:

txn - the transaction used to protect all operations performed with the cursor, or null if the operations should not be transaction protected. If the database is non-transactional, null must be specified. For a transactional database, the transaction is optional for read-only access and required for read-write access.

cursorConfig - The cursor attributes. If null, default attributes are used.

Returns:

A database cursor.

Throws:

DatabasePreemptedException - in a replicated environment if the master has truncated, removed or renamed the database.

OperationFailureException - if this exception occurred earlier and caused the transaction to be invalidated.

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

DatabaseException

delete

public OperationStatus delete(Transaction txn,
                              DatabaseEntry key)
                       throws DeleteConstraintException,
                              LockConflictException,
                              DatabaseException,
                              UnsupportedOperationException,
                              IllegalArgumentException

Deletes the primary key/data pair associated with the specified secondary key. In the presence of duplicate key values, all primary records associated with the designated secondary key will be deleted. When the primary records are deleted, their associated secondary records are deleted as if Database.delete(com.sleepycat.je.Transaction, com.sleepycat.je.DatabaseEntry) were called. This includes, but is not limited to, the secondary record referenced by the given key.

Overrides:

delete in class Database

Parameters:

key - the secondary key used as input. It must be initialized with a non-null byte array by the caller.

txn - For a transactional database, an explicit transaction may be specified, or null may be specified to use auto-commit. For a non-transactional database, null must be specified.

Returns:

The method will return OperationStatus.NOTFOUND if the specified key is not found in the database; otherwise the method will return OperationStatus.SUCCESS.

Throws:

OperationFailureException - if one of the Write Operation Failures occurs.

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

UnsupportedOperationException - if this database is read-only.

IllegalArgumentException - if an invalid parameter is specified.

DeleteConstraintException

LockConflictException

DatabaseException

get

public OperationStatus get(Transaction txn,
                           DatabaseEntry key,
                           DatabaseEntry data,
                           LockMode lockMode)
                    throws DatabaseException

Description copied from class: Database

Retrieves the key/data pair with the given key. If the matching key has duplicate values, the first data item in the set of duplicates is returned. Retrieval of duplicates requires the use of Cursor operations.

Overrides:

get in class Database

Parameters:

key - the secondary key used as input. It must be initialized with a non-null byte array by the caller.

data - the primary data returned as output. Its byte array does not need to be initialized by the caller.

txn - For a transactional database, an explicit transaction may be specified to transaction-protect the operation, or null may be specified to perform the operation without transaction protection. For a non-transactional database, null must be specified.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; otherwise, OperationStatus.SUCCESS.

Throws:

OperationFailureException - if one of the Read Operation Failures occurs.

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

DatabaseException

get

public OperationStatus get(Transaction txn,
                           DatabaseEntry key,
                           DatabaseEntry pKey,
                           DatabaseEntry data,
                           LockMode lockMode)
                    throws DatabaseException

Retrieves the key/data pair with the given key. If the matching key has duplicate values, the first data item in the set of duplicates is returned. Retrieval of duplicates requires the use of Cursor operations.

Parameters:

txn - For a transactional database, an explicit transaction may be specified to transaction-protect the operation, or null may be specified to perform the operation without transaction protection. For a non-transactional database, null must be specified.

key - the secondary key used as input. It must be initialized with a non-null byte array by the caller.

pKey - the primary key returned as output. Its byte array does not need to be initialized by the caller.

data - the primary data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; otherwise, OperationStatus.SUCCESS.

Throws:

OperationFailureException - if one of the Read Operation Failures occurs.

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

IllegalStateException - if the database has been closed.

IllegalArgumentException - if an invalid parameter is specified.

DatabaseException

getSearchBoth

public OperationStatus getSearchBoth(Transaction txn,
                                     DatabaseEntry key,
                                     DatabaseEntry data,
                                     LockMode lockMode)
                              throws UnsupportedOperationException

This operation is not allowed with this method signature. UnsupportedOperationException will always be thrown by this method. The corresponding method with the pKey parameter should be used instead.

Overrides:

getSearchBoth in class Database

Parameters:

txn - For a transactional database, an explicit transaction may be specified to transaction-protect the operation, or null may be specified to perform the operation without transaction protection. For a non-transactional database, null must be specified.

key - the key used as input. It must be initialized with a non-null byte array by the caller.

data - the data used as input. It must be initialized with a non-null byte array by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; otherwise, OperationStatus.SUCCESS.

Throws:

UnsupportedOperationException

getSearchBoth

public OperationStatus getSearchBoth(Transaction txn,
                                     DatabaseEntry key,
                                     DatabaseEntry pKey,
                                     DatabaseEntry data,
                                     LockMode lockMode)
                              throws DatabaseException

Retrieves the key/data pair with the specified secondary and primary key, that is, both the primary and secondary key items must match.

Parameters:

txn - For a transactional database, an explicit transaction may be specified to transaction-protect the operation, or null may be specified to perform the operation without transaction protection. For a non-transactional database, null must be specified.

key - the secondary key used as input. It must be initialized with a non-null byte array by the caller.

pKey - the primary key used as input. It must be initialized with a non-null byte array by the caller.

data - the primary data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; otherwise, OperationStatus.SUCCESS.

Throws:

OperationFailureException - if one of the Read Operation Failures occurs.

EnvironmentFailureException - if an unexpected, internal or environment-wide failure occurs.

IllegalStateException - if the database has been closed.

IllegalArgumentException - if an invalid parameter is specified.

DatabaseException

put

public OperationStatus put(Transaction txn,
                           DatabaseEntry key,
                           DatabaseEntry data)
                    throws UnsupportedOperationException

This operation is not allowed on a secondary database. UnsupportedOperationException will always be thrown by this method. The corresponding method on the primary database should be used instead.

Overrides:

put in class Database

Parameters:

txn - For a transactional database, an explicit transaction may be specified, or null may be specified to use auto-commit. For a non-transactional database, null must be specified.

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.SUCCESS if the operation succeeds.

Throws:

UnsupportedOperationException - if this database is read-only.

putNoOverwrite

public OperationStatus putNoOverwrite(Transaction txn,
                                      DatabaseEntry key,
                                      DatabaseEntry data)
                               throws UnsupportedOperationException

This operation is not allowed on a secondary database. UnsupportedOperationException will always be thrown by this method. The corresponding method on the primary database should be used instead.

Overrides:

putNoOverwrite in class Database

Parameters:

txn - For a transactional database, an explicit transaction may be specified, or null may be specified to use auto-commit. For a non-transactional database, null must be specified.

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.KEYEXIST if the key already appears in the database, else OperationStatus.SUCCESS

Throws:

UnsupportedOperationException - if this database is read-only.

putNoDupData

public OperationStatus putNoDupData(Transaction txn,
                                    DatabaseEntry key,
                                    DatabaseEntry data)
                             throws UnsupportedOperationException

This operation is not allowed on a secondary database. UnsupportedOperationException will always be thrown by this method. The corresponding method on the primary database should be used instead.

Overrides:

putNoDupData in class Database

Parameters:

txn - For a transactional database, an explicit transaction may be specified, or null may be specified to use auto-commit. For a non-transactional database, null must be specified.

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.KEYEXIST if the key/data pair already appears in the database, else OperationStatus.SUCCESS

Throws:

UnsupportedOperationException - if this database is not configured for duplicates, or this database is read-only.

join

public JoinCursor join(Cursor[] cursors,
                       JoinConfig config)
                throws UnsupportedOperationException

This operation is not allowed on a secondary database. UnsupportedOperationException will always be thrown by this method. The corresponding method on the primary database should be used instead.

Overrides:

join in class Database

Parameters:

cursors - an array of cursors associated with this primary database. In a replicated environment, an explicit transaction must be specified when opening each cursor, unless read-uncommitted isolation is isolation is specified via the CursorConfig or LockMode parameter.

config - The join attributes. If null, default attributes are used.

Returns:

a specialized cursor that returns the results of the equality join operation.

Throws:

UnsupportedOperationException

See Also:

JoinCursor