Module org.eclipse.persistence.core
Package org.eclipse.persistence.mappings

Class ManyToManyMapping

java.lang.Object
org.eclipse.persistence.core.mappings.CoreMapping<AttributeAccessor,AbstractSession,ContainerPolicy,ClassDescriptor,DatabaseField>
org.eclipse.persistence.mappings.DatabaseMapping
org.eclipse.persistence.mappings.ForeignReferenceMapping
org.eclipse.persistence.mappings.CollectionMapping
org.eclipse.persistence.mappings.ManyToManyMapping
All Implemented Interfaces:
Serializable, Cloneable, ContainerMapping, MapComponentMapping, RelationalMapping
public class ManyToManyMapping extends CollectionMapping implements RelationalMapping, MapComponentMapping

Purpose: Many to many mappings are used to represent the relationships between a collection of source objects and a collection of target objects. The mapping requires the creation of an intermediate table for managing the associations between the source and target records.

Since:
TOPLink/Java 1.0
See Also:

  • Field Details

    • PostInsert

      protected static final String PostInsert
      Used for data modification events.
      See Also:

    • ObjectRemoved

      protected static final String ObjectRemoved
      See Also:

    • ObjectAdded

      protected static final String ObjectAdded
      See Also:

    • mechanism

      protected RelationTableMechanism mechanism
      Mechanism holds relationTable and all fields and queries associated with it.

    • historyPolicy

      protected HistoryPolicy historyPolicy

    • isDefinedAsOneToManyMapping

      protected boolean isDefinedAsOneToManyMapping
      266912: Since: EclipseLink 2.0 for the Metamodel API For 1:1 and m:m mappings - track the original externally defined mapping if different Note: This field will provide differentiation for the following external to internal representations for mapping types
      - A OneToManyMapping will be represented by a ManyToManyMapping if unidirectional
      - A ManyToOneMapping will be represented by a OneToOneMapping (without a FK constraint)

  • Constructor Details

    • ManyToManyMapping

      public ManyToManyMapping()
      PUBLIC: Default constructor.

  • Method Details

    • isOwned

      public boolean isOwned()
      INTERNAL:
      Overrides:
      isOwned in class DatabaseMapping

    • isRelationalMapping

      public boolean isRelationalMapping()
      INTERNAL:
      Overrides:
      isRelationalMapping in class DatabaseMapping

    • addSourceRelationKeyField

      public void addSourceRelationKeyField(DatabaseField sourceRelationKeyField, DatabaseField sourcePrimaryKeyField)
      PUBLIC: Add the fields in the intermediate table that corresponds to the primary key in the source table. This method is used if the keys are composite.

    • addSourceRelationKeyFieldName

      public void addSourceRelationKeyFieldName(String sourceRelationKeyFieldName, String sourcePrimaryKeyFieldName)
      PUBLIC: Add the fields in the intermediate table that corresponds to the primary key in the source table. This method is used if the keys are composite.

    • addTargetRelationKeyField

      public void addTargetRelationKeyField(DatabaseField targetRelationKeyField, DatabaseField targetPrimaryKeyField)
      PUBLIC: Add the fields in the intermediate table that corresponds to the primary key in the target table. This method is used if the keys are composite.

    • addTargetRelationKeyFieldName

      public void addTargetRelationKeyFieldName(String targetRelationKeyFieldName, String targetPrimaryKeyFieldName)
      PUBLIC: Add the fields in the intermediate table that corresponds to the primary key in the target table. This method is used if the keys are composite.

    • collectQueryParameters

      public void collectQueryParameters(Set<DatabaseField> cacheFields)
      INTERNAL: This method is used to store the FK fields that can be cached that correspond to noncacheable mappings the FK field values will be used to re-issue the query when cloning the shared cache entity
      Overrides:
      collectQueryParameters in class CollectionMapping
      Parameters:
      cacheFields - TODO

    • clone

      public Object clone()
      INTERNAL: The mapping clones itself to create deep copy.
      Specified by:
      clone in interface MapComponentMapping
      Overrides:
      clone in class CollectionMapping
      Returns:
      new instance of itself

    • earlyPreDelete

      public void earlyPreDelete(DeleteObjectQuery query, Object object)
      INTERNAL: Delete join tables before the start of the deletion process to avoid constraint errors.
      Overrides:
      earlyPreDelete in class DatabaseMapping
      Parameters:
      query - TODO
      object - TODO

    • createMapComponentFromRow

      public Object createMapComponentFromRow(AbstractRecord dbRow, ObjectBuildingQuery query, CacheKey parentCacheKey, AbstractSession session, boolean isTargetProtected)
      INTERNAL Called when a DatabaseMapping is used to map the key in a collection. Returns the key.
      Specified by:
      createMapComponentFromRow in interface MapComponentMapping

    • extendPessimisticLockScopeInTargetQuery

      protected void extendPessimisticLockScopeInTargetQuery(ObjectLevelReadQuery targetQuery, ObjectBuildingQuery sourceQuery)
      INTERNAL: Adds locking clause to the target query to extend pessimistic lock scope.
      Overrides:
      extendPessimisticLockScopeInTargetQuery in class ForeignReferenceMapping

    • extendPessimisticLockScopeInSourceQuery

      public void extendPessimisticLockScopeInSourceQuery(ObjectLevelReadQuery sourceQuery)
      INTERNAL: Called only if both shouldExtendPessimisticLockScope and shouldExtendPessimisticLockScopeInSourceQuery are true. Adds fields to be locked to the where clause of the source query. Note that the sourceQuery must be ObjectLevelReadQuery so that it has ExpressionBuilder. This method must be implemented in subclasses that allow setting shouldExtendPessimisticLockScopeInSourceQuery to true.
      Overrides:
      extendPessimisticLockScopeInSourceQuery in class ForeignReferenceMapping

    • extractKeyFromTargetRow

      protected Object extractKeyFromTargetRow(AbstractRecord row, AbstractSession session)
      INTERNAL: Extract the source primary key value from the relation row. Used for batch reading, most following same order and fields as in the mapping.
      Overrides:
      extractKeyFromTargetRow in class CollectionMapping

    • extractBatchKeyFromRow

      protected Object extractBatchKeyFromRow(AbstractRecord row, AbstractSession session)
      INTERNAL: Extract the primary key value from the source row. Used for batch reading, most following same order and fields as in the mapping.
      Overrides:
      extractBatchKeyFromRow in class ForeignReferenceMapping

    • buildBatchCriteria

      protected Expression buildBatchCriteria(ExpressionBuilder builder, ObjectLevelReadQuery query)
      INTERNAL: Return the selection criteria used to IN batch fetching.
      Overrides:
      buildBatchCriteria in class ForeignReferenceMapping

    • postPrepareNestedBatchQuery

      protected void postPrepareNestedBatchQuery(ReadQuery batchQuery, ObjectLevelReadQuery query)
      INTERNAL: Add additional fields and check for history.
      Overrides:
      postPrepareNestedBatchQuery in class CollectionMapping

    • getAdditionalFieldsBaseExpression

      protected Expression getAdditionalFieldsBaseExpression(ReadQuery query)
      INTERNAL: Return the base expression to use for adding fields to the query. Normally this is the query's builder, but may be the join table for m-m.
      Overrides:
      getAdditionalFieldsBaseExpression in class CollectionMapping

    • getDeleteQuery

      protected DataModifyQuery getDeleteQuery()

    • getExtendPessimisticLockScopeDedicatedQuery

      protected ReadQuery getExtendPessimisticLockScopeDedicatedQuery(AbstractSession session, short lockMode)
      INTERNAL: Should be overridden by subclass that allows setting extendPessimisticLockScope to DEDICATED_QUERY.
      Overrides:
      getExtendPessimisticLockScopeDedicatedQuery in class ForeignReferenceMapping

    • getFieldsForTranslationInAggregate

      public Collection getFieldsForTranslationInAggregate()
      INTERNAL: Return source key fields for translation by an AggregateObjectMapping
      Overrides:
      getFieldsForTranslationInAggregate in class ForeignReferenceMapping

    • getInsertQuery

      protected DataModifyQuery getInsertQuery()

    • getJoinCriteria

      public Expression getJoinCriteria(ObjectExpression context, Expression base)
      INTERNAL: Returns the join criteria stored in the mapping selection query. This criteria is used to read reference objects across the tables from the database.
      Overrides:
      getJoinCriteria in class CollectionMapping

    • getHistoryPolicy

      public HistoryPolicy getHistoryPolicy()
      PUBLIC: Allows history tracking on the m-m join table.

    • getRelationTableMechanism

      public RelationTableMechanism getRelationTableMechanism()
      PUBLIC: Returns RelationTableMechanism that may be owned by the mapping. Note that all RelationTableMechanism methods are accessible through the mapping directly. The only reason this method is provided is to allow a uniform approach to RelationTableMechanism in both ManyToManyMapping and OneToOneMapping that uses RelationTableMechanism.

    • getRelationTable

      public DatabaseTable getRelationTable()
      INTERNAL: Return the relation table associated with the mapping.

    • getRelationTableName

      public String getRelationTableName()
      PUBLIC: Return the relation table name associated with the mapping.

    • getRelationTableQualifiedName

      public String getRelationTableQualifiedName()
      PUBLIC: Return the relation table qualified name associated with the mapping.

    • getSourceKeyFieldNames

      public Vector getSourceKeyFieldNames()
      PUBLIC: Return the source key field names associated with the mapping. These are in-order with the sourceRelationKeyFieldNames.

    • getSourceKeyFields

      public Vector<DatabaseField> getSourceKeyFields()
      INTERNAL: Return all the source key fields associated with the mapping.

    • getSourceRelationKeyFieldNames

      public Vector getSourceRelationKeyFieldNames()
      PUBLIC: Return the source relation key field names associated with the mapping. These are in-order with the sourceKeyFieldNames.

    • getSourceRelationKeyFields

      public Vector<DatabaseField> getSourceRelationKeyFields()
      INTERNAL: Return all the source relation key fields associated with the mapping.

    • getTargetKeyFieldNames

      public Vector getTargetKeyFieldNames()
      PUBLIC: Return the target key field names associated with the mapping. These are in-order with the targetRelationKeyFieldNames.

    • getTargetKeyFields

      public Vector<DatabaseField> getTargetKeyFields()
      INTERNAL: Return all the target keys associated with the mapping.

    • getTargetRelationKeyFieldNames

      public Vector getTargetRelationKeyFieldNames()
      PUBLIC: Return the target relation key field names associated with the mapping. These are in-order with the targetKeyFieldNames.

    • getTargetRelationKeyFields

      public Vector<DatabaseField> getTargetRelationKeyFields()
      INTERNAL: Return all the target relation key fields associated with the mapping.

    • hasCustomDeleteQuery

      protected boolean hasCustomDeleteQuery()

    • hasCustomInsertQuery

      protected boolean hasCustomInsertQuery()

    • hasDependency

      public boolean hasDependency()
      INTERNAL: The join table is a dependency if not read-only.
      Overrides:
      hasDependency in class ForeignReferenceMapping

    • initialize

      public void initialize(AbstractSession session) throws DescriptorException
      INTERNAL: Initialize mappings
      Overrides:
      initialize in class CollectionMapping
      Throws:
      DescriptorException

    • buildListOrderField

      protected void buildListOrderField()
      INTERNAL: Verifies listOrderField's table: it must be relation table. Precondition: listOrderField != null.
      Overrides:
      buildListOrderField in class CollectionMapping

    • shouldUseListOrderFieldTableExpression

      public boolean shouldUseListOrderFieldTableExpression()
      INTERNAL: Indicates whether getListOrderFieldExpression method should create field expression on table expression.
      Overrides:
      shouldUseListOrderFieldTableExpression in class CollectionMapping

    • initializeChangeOrderTargetQuery

      protected void initializeChangeOrderTargetQuery(AbstractSession session)
      INTERNAL: Initialize changeOrderTargetQuery.
      Overrides:
      initializeChangeOrderTargetQuery in class CollectionMapping

    • initializeDeleteAllQuery

      protected void initializeDeleteAllQuery(AbstractSession session)
      Initialize delete all query. This query is used to all relevant rows from the relation table.

    • initializeListOrderFieldTable

      protected void initializeListOrderFieldTable(AbstractSession session)
      INTERNAL: Initializes listOrderField's table. Precondition: listOrderField != null.
      Overrides:
      initializeListOrderFieldTable in class CollectionMapping

    • initializeSelectionCriteriaAndAddFieldsToQuery

      protected void initializeSelectionCriteriaAndAddFieldsToQuery(Expression startCriteria)
      INTERNAL: Selection criteria is created to read target records from the table.

    • insertAddedObjectEntry

      protected void insertAddedObjectEntry(ObjectLevelModifyQuery query, Object objectAdded, Map extraData) throws DatabaseException, OptimisticLockException
      INTERNAL: An object was added to the collection during an update, insert it.
      Throws:
      DatabaseException
      OptimisticLockException

    • insertIntoRelationTable

      public void insertIntoRelationTable(WriteObjectQuery query) throws DatabaseException
      INTERNAL: Insert into relation table. This follows following steps.

      - Extract primary key and its value from the source object.

      - Extract target key and its value from the target object.

      - Construct a insert statement with above fields and values for relation table.

      - execute the statement.

      - Repeat above three statements until all the target objects are done.

      Throws:
      DatabaseException

    • insertTargetObjects

      public void insertTargetObjects(WriteObjectQuery query) throws DatabaseException, OptimisticLockException
      INTERNAL: Write the target objects if the cascade policy requires them to be written first. They must be written within a unit of work to ensure that they exist.
      Throws:
      DatabaseException
      OptimisticLockException

    • isDefinedAsOneToManyMapping

      public boolean isDefinedAsOneToManyMapping()
      INTERNAL: Return whether this mapping was originally defined as a OneToMany.

    • isJoiningSupported

      public boolean isJoiningSupported()
      INTERNAL: Return if this mapping support joining.
      Overrides:
      isJoiningSupported in class ForeignReferenceMapping

    • isManyToManyMapping

      public boolean isManyToManyMapping()
      Description copied from class: DatabaseMapping
      INTERNAL: Related mapping should implement this method to return true.
      Overrides:
      isManyToManyMapping in class DatabaseMapping

    • postInitialize

      public void postInitialize(AbstractSession session)
      INTERNAL: Ensure the container policy is post initialized
      Overrides:
      postInitialize in class CollectionMapping

    • objectAddedDuringUpdate

      protected void objectAddedDuringUpdate(ObjectLevelModifyQuery query, Object objectAdded, ObjectChangeSet changeSet, Map extraData) throws DatabaseException, OptimisticLockException
      INTERNAL: An object was added to the collection during an update, insert it if private.
      Overrides:
      objectAddedDuringUpdate in class CollectionMapping
      Throws:
      DatabaseException
      OptimisticLockException

    • objectRemovedDuringUpdate

      protected void objectRemovedDuringUpdate(ObjectLevelModifyQuery query, Object objectDeleted, Map extraData) throws DatabaseException, OptimisticLockException
      INTERNAL: An object was removed to the collection during an update, delete it if private.
      Overrides:
      objectRemovedDuringUpdate in class CollectionMapping
      Throws:
      DatabaseException
      OptimisticLockException

    • objectOrderChangedDuringUpdate

      protected void objectOrderChangedDuringUpdate(WriteObjectQuery query, Object orderChangedObject, int orderIndex)
      Overrides:
      objectOrderChangedDuringUpdate in class CollectionMapping

    • performDataModificationEvent

      public void performDataModificationEvent(Object[] event, AbstractSession session) throws DatabaseException, DescriptorException
      INTERNAL: Perform the commit event. This is used in the uow to delay data modifications.
      Overrides:
      performDataModificationEvent in class DatabaseMapping
      Throws:
      DatabaseException
      DescriptorException

    • postInsert

      public void postInsert(WriteObjectQuery query) throws DatabaseException
      INTERNAL: Insert into relation table. This follows following steps.

      - Extract primary key and its value from the source object.

      - Extract target key and its value from the target object.

      - Construct a insert statement with above fields and values for relation table.

      - execute the statement.

      - Repeat above three statements until all the target objects are done.

      Overrides:
      postInsert in class CollectionMapping
      Throws:
      DatabaseException

    • postUpdate

      public void postUpdate(WriteObjectQuery query) throws DatabaseException
      INTERNAL: Update the relation table with the entries related to this mapping. Delete entries removed, insert entries added. If private also insert/delete/update target objects.
      Overrides:
      postUpdate in class DatabaseMapping
      Throws:
      DatabaseException

    • preDelete

      public void preDelete(DeleteObjectQuery query) throws DatabaseException
      INTERNAL: Delete entries related to this mapping from the relation table.
      Overrides:
      preDelete in class DatabaseMapping
      Throws:
      DatabaseException

    • prepareTranslationRow

      protected void prepareTranslationRow(AbstractRecord translationRow, Object object, ClassDescriptor descriptor, AbstractSession session)
      INTERNAL: The translation row may require additional fields than the primary key if the mapping in not on the primary key.
      Overrides:
      prepareTranslationRow in class CollectionMapping

    • setCustomDeleteQuery

      public void setCustomDeleteQuery(DataModifyQuery query)
      PUBLIC: The default delete query for mapping can be overridden by specifying the new query. This query must delete the row from the M-M join table.

    • setCustomInsertQuery

      public void setCustomInsertQuery(DataModifyQuery query)
      PUBLIC: The default insert query for mapping can be overridden by specifying the new query. This query must insert the row into the M-M join table.

    • setDeleteQuery

      protected void setDeleteQuery(DataModifyQuery deleteQuery)

    • setDeleteSQLString

      public void setDeleteSQLString(String sqlString)
      PUBLIC: Set the receiver's delete SQL string. This allows the user to override the SQL generated by TOPLink, with there own SQL or procedure call. The arguments are translated from the fields of the source row, through replacing the field names marked by '#' with the values for those fields. This is used to delete a single entry from the M-M join table. Example, 'delete from PROJ_EMP where PROJ_ID = #PROJ_ID AND EMP_ID = #EMP_ID'.

    • setDefinedAsOneToManyMapping

      public void setDefinedAsOneToManyMapping(boolean isDefinedAsOneToManyMapping)
      INTERNAL: Set whether this mapping was originally defined as a OneToMany

    • setDeleteCall

      public void setDeleteCall(Call call)
      PUBLIC: Set the receiver's delete Call. This allows the user to override the SQL generated by TOPLink, with there own SQL or procedure call. The arguments are translated from the fields of the source row. This is used to delete a single entry from the M-M join table. Example, 'new SQLCall("delete from PROJ_EMP where PROJ_ID = #PROJ_ID AND EMP_ID = #EMP_ID")'.

    • setInsertQuery

      protected void setInsertQuery(DataModifyQuery insertQuery)

    • setInsertSQLString

      public void setInsertSQLString(String sqlString)
      PUBLIC: Set the receiver's insert SQL string. This allows the user to override the SQL generated by TOPLink, with there own SQL or procedure call. The arguments are translated from the fields of the source row, through replacing the field names marked by '#' with the values for those fields. This is used to insert an entry into the M-M join table. Example, 'insert into PROJ_EMP (EMP_ID, PROJ_ID) values (#EMP_ID, #PROJ_ID)'.

    • setInsertCall

      public void setInsertCall(Call call)
      PUBLIC: Set the receiver's insert Call. This allows the user to override the SQL generated by TOPLink, with there own SQL or procedure call. The arguments are translated from the fields of the source row. This is used to insert an entry into the M-M join table. Example, 'new SQLCall("insert into PROJ_EMP (EMP_ID, PROJ_ID) values (#EMP_ID, #PROJ_ID)")'.

    • setRelationTable

      public void setRelationTable(DatabaseTable relationTable)
      PUBLIC: Set the relational table. This is the join table that store both the source and target primary keys.

    • setHistoryPolicy

      public void setHistoryPolicy(HistoryPolicy policy)
      PUBLIC: Enable history tracking on the m-m join table.

    • setRelationTableName

      public void setRelationTableName(String tableName)
      PUBLIC: Set the name of the relational table. This is the join table that store both the source and target primary keys.

    • setSessionName

      public void setSessionName(String name)
      PUBLIC: Set the name of the session to execute the mapping's queries under. This can be used by the session broker to override the default session to be used for the target class.
      Overrides:
      setSessionName in class CollectionMapping

    • setSourceKeyFieldNames

      public void setSourceKeyFieldNames(Vector fieldNames)
      PUBLIC: Set the source key field names associated with the mapping. These must be in-order with the sourceRelationKeyFieldNames.

    • setSourceKeyFields

      public void setSourceKeyFields(Vector<DatabaseField> sourceKeyFields)
      INTERNAL: Set the source fields.

    • setSourceRelationKeyFieldName

      public void setSourceRelationKeyFieldName(String sourceRelationKeyFieldName)
      PUBLIC: Set the source key field in the relation table. This is the name of the foreign key in the relation table to the source's primary key field. This method is used if the source primary key is a singleton only.

    • setSourceRelationKeyFieldNames

      public void setSourceRelationKeyFieldNames(Vector fieldNames)
      PUBLIC: Set the source relation key field names associated with the mapping. These must be in-order with the sourceKeyFieldNames.

    • setSourceRelationKeyFields

      public void setSourceRelationKeyFields(Vector<DatabaseField> sourceRelationKeyFields)
      INTERNAL: Set the source fields.

    • setTargetKeyFieldNames

      public void setTargetKeyFieldNames(Vector fieldNames)
      INTERNAL: Set the target key field names associated with the mapping. These must be in-order with the targetRelationKeyFieldNames.

    • setTargetKeyFields

      public void setTargetKeyFields(Vector<DatabaseField> targetKeyFields)
      INTERNAL: Set the target fields.

    • setTargetRelationKeyFieldName

      public void setTargetRelationKeyFieldName(String targetRelationKeyFieldName)
      PUBLIC: Set the target key field in the relation table. This is the name of the foreign key in the relation table to the target's primary key field. This method is used if the target's primary key is a singleton only.

    • setTargetRelationKeyFieldNames

      public void setTargetRelationKeyFieldNames(Vector fieldNames)
      INTERNAL: Set the target relation key field names associated with the mapping. These must be in-order with the targetKeyFieldNames.

    • setTargetRelationKeyFields

      public void setTargetRelationKeyFields(Vector<DatabaseField> targetRelationKeyFields)
      INTERNAL: Set the target fields.

    • prepareHistoricalQuery

      protected ReadQuery prepareHistoricalQuery(ReadQuery targetQuery, ObjectBuildingQuery sourceQuery, AbstractSession executionSession)
      INTERNAL: Append the temporal selection to the query selection criteria.
      Overrides:
      prepareHistoricalQuery in class ForeignReferenceMapping