com.sleepycat.db
Class SecondaryConfig

java.lang.Object
  com.sleepycat.db.DatabaseConfig
      com.sleepycat.db.SecondaryConfig

All Implemented Interfaces:

Cloneable

public class SecondaryConfig
extends DatabaseConfig
implements Cloneable

The configuration properties of a SecondaryDatabase extend those of a primary Database. The secondary database configuration is specified when calling Environment.openSecondaryDatabase.

To create a configuration object with default attributes:

    SecondaryConfig config = new SecondaryConfig();

    SecondaryConfig config = new SecondaryConfig();
    config.setAllowCreate(true);
    config.setSortedDuplicates(true);
    config.setKeyCreator(new MyKeyCreator());

NOTE: There are two situations where the use of secondary databases without transactions requires special consideration. When using a transactional database or when doing read operations only, this note does not apply.

• If secondary is configured to not allow duplicates, when the secondary is being updated it is possible that an error will occur when the secondary key value in a record being added is already present in the database. A DatabaseException will be thrown in this situation.
• If a foreign key constraint is configured with the delete action ABORT (the default setting), a DatabaseException will be thrown if an attempt is made to delete a referenced foreign key.

See Also:

Environment.openSecondaryDatabase, SecondaryDatabase

DEFAULT

public static final SecondaryConfig DEFAULT

SecondaryConfig

public SecondaryConfig()

Creates an instance with the system's default settings.

setAllowPopulate

public void setAllowPopulate(boolean allowPopulate)

Specifies whether automatic population of the secondary is allowed.

If automatic population is allowed, when the secondary database is opened it is checked to see if it is empty. If it is empty, the primary database is read in its entirety and keys are added to the secondary database using the information read from the primary.

If this property is set to true and the database is transactional, the population of the secondary will be done within the explicit or auto-commit transaction that is used to open the database.

Parameters:

allowPopulate - whether automatic population of the secondary is allowed.

getAllowPopulate

public boolean getAllowPopulate()

Returns whether automatic population of the secondary is allowed. If setAllowPopulate(boolean) has not been called, this method returns false.

Returns:

whether automatic population of the secondary is allowed.

See Also:

setAllowPopulate(boolean)

setImmutableSecondaryKey

public void setImmutableSecondaryKey(boolean immutableSecondaryKey)

Specifies whether the secondary key is immutable.

Specifying that a secondary key is immutable can be used to optimize updates when the secondary key in a primary record will never be changed after that primary record is inserted. For immutable secondary keys, a best effort is made to avoid calling SecondaryKeyCreator.createSecondaryKey when a primary record is updated. This optimization may reduce the overhead of an update operation significantly if the createSecondaryKey operation is expensive.

Be sure to set this property to true only if the secondary key in the primary record is never changed. If this rule is violated, the secondary index will become corrupted, that is, it will become out of sync with the primary.

Parameters:

immutableSecondaryKey - whether the secondary key is immutable.

getImmutableSecondaryKey

public boolean getImmutableSecondaryKey()

Returns whether the secondary key is immutable. If setImmutableSecondaryKey(boolean) has not been called, this method returns false.

Returns:

whether the secondary key is immutable.

See Also:

setImmutableSecondaryKey(boolean)

setKeyCreator

public void setKeyCreator(SecondaryKeyCreator keyCreator)

Specifies the user-supplied object used for creating single-valued secondary keys.

Unless the primary database is read-only, a key creator is required when opening a secondary database. Either a KeyCreator or MultiKeyCreator must be specified, but both may not be specified.

Unless the primary database is read-only, a key creator is required when opening a secondary database.

Parameters:

keyCreator - the user-supplied object used for creating single-valued secondary keys.

getKeyCreator

public SecondaryKeyCreator getKeyCreator()

Returns the user-supplied object used for creating single-valued secondary keys.

Returns:

the user-supplied object used for creating single-valued secondary keys.

See Also:

setKeyCreator(com.sleepycat.db.SecondaryKeyCreator)

setMultiKeyCreator

public void setMultiKeyCreator(SecondaryMultiKeyCreator multiKeyCreator)

Specifies the user-supplied object used for creating multi-valued secondary keys.

Unless the primary database is read-only, a key creator is required when opening a secondary database. Either a KeyCreator or MultiKeyCreator must be specified, but both may not be specified.

Parameters:

multiKeyCreator - the user-supplied object used for creating multi-valued secondary keys.

getMultiKeyCreator

public SecondaryMultiKeyCreator getMultiKeyCreator()

Returns the user-supplied object used for creating multi-valued secondary keys.

Returns:

the user-supplied object used for creating multi-valued secondary keys.

See Also:

setKeyCreator(com.sleepycat.db.SecondaryKeyCreator)

setForeignKeyDatabase

public void setForeignKeyDatabase(Database foreignDb)

Defines a foreign key integrity constraint for a given foreign key database.

If this property is non-null, a record must be present in the specified foreign database for every record in the secondary database, where the secondary key value is equal to the foreign database key value. Whenever a record is to be added to the secondary database, the secondary key is used as a lookup key in the foreign database.

The foreign database must not have duplicates allowed.

Parameters:

foreignDb - the database used to check the foreign key integrity constraint, or null if no foreign key constraint should be checked.

getForeignKeyDatabase

public com.sleepycat.db.internal.Db getForeignKeyDatabase()

Returns the database used to check the foreign key integrity constraint, or null if no foreign key constraint will be checked.

Returns:

the foreign key database, or null.

See Also:

setForeignKeyDatabase(com.sleepycat.db.Database)

setForeignKeyDeleteAction

public void setForeignKeyDeleteAction(ForeignKeyDeleteAction action)

Specifies the action taken when a referenced record in the foreign key database is deleted.

This property is ignored if the foreign key database property is null.

Parameters:

action - the action taken when a referenced record in the foreign key database is deleted.

See Also:

@see #setForeignKeyDatabase

getForeignKeyDeleteAction

public ForeignKeyDeleteAction getForeignKeyDeleteAction()

Returns the action taken when a referenced record in the foreign key database is deleted.

Returns:

the action taken when a referenced record in the foreign key database is deleted.

See Also:

setForeignKeyDeleteAction(com.sleepycat.db.ForeignKeyDeleteAction)

setForeignKeyNullifier

public void setForeignKeyNullifier(ForeignKeyNullifier keyNullifier)

Specifies the user-supplied object used for setting single-valued foreign keys to null.

This method may not be used along with setMultiKeyCreator(com.sleepycat.db.SecondaryMultiKeyCreator). When using a multi-key creator, use setForeignMultiKeyNullifier(com.sleepycat.db.ForeignMultiKeyNullifier) instead.

If the foreign key database property is non-null and the foreign key delete action is NULLIFY, this property is required to be non-null; otherwise, this property is ignored.

WARNING: Key nullifier instances are shared by multiple threads and key nullifier methods are called without any special synchronization. Therefore, key creators must be thread safe. In general no shared state should be used and any caching of computed values must be done with proper synchronization.

Parameters:

keyNullifier - the user-supplied object used for setting single-valued foreign keys to null.

See Also:

@see ForeignKeyDeleteAction#NULLIFY @see #setForeignKeyDatabase

getForeignKeyNullifier

public ForeignKeyNullifier getForeignKeyNullifier()

Returns the user-supplied object used for setting single-valued foreign keys to null.

Returns:

the user-supplied object used for setting single-valued foreign keys to null.

See Also:

setForeignKeyNullifier(com.sleepycat.db.ForeignKeyNullifier)

setForeignMultiKeyNullifier

public void setForeignMultiKeyNullifier(ForeignMultiKeyNullifier multiKeyNullifier)

Specifies the user-supplied object used for setting multi-valued foreign keys to null.

If the foreign key database property is non-null and the foreign key delete action is NULLIFY, this property is required to be non-null; otherwise, this property is ignored.

WARNING: Key nullifier instances are shared by multiple threads and key nullifier methods are called without any special synchronization. Therefore, key creators must be thread safe. In general no shared state should be used and any caching of computed values must be done with proper synchronization.

Parameters:

multiKeyNullifier - the user-supplied object used for setting multi-valued foreign keys to null.

See Also:

@see ForeignKeyDeleteAction#NULLIFY @see #setForeignKeyDatabase

getForeignMultiKeyNullifier

public ForeignMultiKeyNullifier getForeignMultiKeyNullifier()

Returns the user-supplied object used for setting multi-valued foreign keys to null.

Returns:

the user-supplied object used for setting multi-valued foreign keys to null.

See Also:

setForeignMultiKeyNullifier(com.sleepycat.db.ForeignMultiKeyNullifier)