Apache OpenJPA 2.0 User's Guide - Apache HTTP Server

408 Pages·2009·3.16 MB·English

Apache OpenJPA 2.0 User's Guide
Apache OpenJPA 2.0 User's Guide

1.Introduction ............................................................................................................................................. 1
1.About ............................................................................................................................................. 3
2.Legal .............................................................................................................................................. 4
2.1.License ................................................................................................................................ 4
2.2.Notice .................................................................................................................................. 4
2.3.Copyrights ............................................................................................................................ 4
2.3.1.Apache ...................................................................................................................... 4
2.3.2.Serp .......................................................................................................................... 4
2.3.3.Sun ........................................................................................................................... 4
2.3.4.Other ......................................................................................................................... 5
2.JavaPersistenceAPI ................................................................................................................................. 6
1.Introduction ....................................................................................................................................11
1.1.IntendedAudience.................................................................................................................11
1.2.LightweightPersistence ..........................................................................................................11
2.WhyJPA? ......................................................................................................................................12
3.JavaPersistenceAPIArchitecture .......................................................................................................14
3.1.JPAExceptions.....................................................................................................................15
4.Entity ............................................................................................................................................17
4.1.RestrictionsonPersistentClasses .............................................................................................18
4.1.1.DefaultorNo-ArgConstructor ......................................................................................18
4.1.2.Final ........................................................................................................................18
4.1.3.IdentityFields ............................................................................................................18
4.1.4.VersionField .............................................................................................................18
4.1.5.Inheritance ................................................................................................................19
4.1.6.PersistentFields .........................................................................................................19
4.1.7.Conclusions ...............................................................................................................20
4.2.EntityIdentity ......................................................................................................................20
4.2.1.IdentityClass .............................................................................................................21
4.2.1.1.IdentityHierarchies ..........................................................................................22
4.3.LifecycleCallbacks ...............................................................................................................23
4.3.1.CallbackMethods .......................................................................................................23
4.3.2.UsingCallbackMethods ..............................................................................................24
4.3.3.UsingEntityListeners .................................................................................................24
4.3.4.EntityListenersHierarchy ............................................................................................25
4.4.Conclusions .........................................................................................................................26
5.Metadata ........................................................................................................................................27
5.1.ClassMetadata .....................................................................................................................28
5.1.1.Entity .......................................................................................................................28
5.1.2.IdClass.....................................................................................................................29
5.1.3.MappedSuperclass .....................................................................................................29
5.1.4.Embeddable ...............................................................................................................29
5.1.5.EntityListeners ...........................................................................................................30
5.1.6.Example ...................................................................................................................30
5.2.FieldandPropertyMetadata ....................................................................................................31
5.2.1.ExplicitAccess...........................................................................................................32
5.2.2.Transient ...................................................................................................................33
5.2.3.Id.............................................................................................................................34
5.2.4.GeneratedValue .........................................................................................................34
5.2.5.EmbeddedId .............................................................................................................35
5.2.6.Version .....................................................................................................................35
5.2.7.Basic ........................................................................................................................35
5.2.7.1.FetchType ......................................................................................................36
5.2.8.Embedded .................................................................................................................36
5.2.9.ManyToOne.............................................................................................................36
5.2.9.1.CascadeType ..................................................................................................37
5.2.10.OneToMany ...........................................................................................................38
5.2.10.1.BidirectionalRelations ....................................................................................39
5.2.11.OneToOne .............................................................................................................39
iv
ApacheOpenJPA2.0User'sGuide
5.2.12.ManyToMany .........................................................................................................40
5.2.13.OrderBy .................................................................................................................41
5.2.14.MapKey .................................................................................................................41
5.2.15.PersistentFieldDefaults .............................................................................................41
5.3.XMLSchema .......................................................................................................................42
5.4.Conclusion...........................................................................................................................60
6.Persistence .....................................................................................................................................65
6.1.persistence.xml .....................................................................................................................65
6.2.Non-EEUse .........................................................................................................................70
7.EntityManagerFactory ......................................................................................................................71
7.1.ObtaininganEntityManagerFactory..........................................................................................71
7.2.ObtainingEntityManagers ......................................................................................................71
7.3.PersistenceContext ...............................................................................................................72
7.3.1.TransactionPersistenceContext ....................................................................................72
7.3.2.ExtendedPersistenceContext........................................................................................73
7.4.RetrievingPropertiesInformation.............................................................................................74
7.5.ClosingtheEntityManagerFactory............................................................................................74
7.6.PersistenceUnitUtil ................................................................................................................74
8.EntityManager ................................................................................................................................76
8.1.TransactionAssociation..........................................................................................................76
8.2.EntityLifecycleManagement ..................................................................................................77
8.3.LifecycleExamples ...............................................................................................................80
8.4.EntityIdentityManagement ....................................................................................................82
8.5.CacheManagement ...............................................................................................................82
8.6.QueryFactory ......................................................................................................................83
8.7.RetrievingPropertiesInformation.............................................................................................84
8.8.Closing ...............................................................................................................................84
9.Transaction.....................................................................................................................................85
9.1.TransactionTypes .................................................................................................................85
9.2.TheEntityTransactionInterface ...............................................................................................86
10.JPAQuery ....................................................................................................................................88
10.1.JPQLAPI ..........................................................................................................................88
10.1.1.QueryBasics ............................................................................................................88
10.1.2.RelationTraversal .....................................................................................................91
10.1.3.EmbeddableTraversal................................................................................................92
10.1.4.FetchJoins...............................................................................................................93
10.1.5.JPQLFunctions ........................................................................................................93
10.1.6.PolymorphicQueries .................................................................................................95
10.1.7.QueryParameters ......................................................................................................95
10.1.8.QueryHints .............................................................................................................96
10.1.8.1.LockingHints ................................................................................................96
10.1.8.2.LockTimeoutHint .........................................................................................97
10.1.8.3.QueryTimeoutHint ........................................................................................97
10.1.8.4.ResultSetSizeHint ........................................................................................97
10.1.8.5.IsolationLevelHint ........................................................................................97
10.1.8.6.OtherFetchplanHints......................................................................................97
10.1.8.7.Database-SpecificHints ...................................................................................97
10.1.8.8.NamedQueryHints ........................................................................................98
10.1.8.9.HandlingofMultipleSimilarQueryHints ...........................................................98
10.1.9.Ordering..................................................................................................................98
10.1.10.Aggregates .............................................................................................................99
10.1.11.NamedQueries .......................................................................................................99
10.1.12.DeleteByQuery ...................................................................................................100
10.1.13.UpdateByQuery ..................................................................................................100
10.2.JPQLLanguageReference ..................................................................................................101
10.2.1.JPQLStatementTypes .............................................................................................101
10.2.1.1.JPQLSelectStatement ..................................................................................101
10.2.1.2.JPQLUpdateandDeleteStatements ................................................................102
10.2.2.JPQLAbstractSchemaTypesandQueryDomains ........................................................102
v
ApacheOpenJPA2.0User'sGuide
10.2.2.1.JPQLEntityNaming .....................................................................................102
10.2.2.2.JPQLSchemaExample..................................................................................102
10.2.3.JPQLFROMClauseandNavigationalDeclarations.......................................................103
10.2.3.1.JPQLFROMIdentifiers .................................................................................104
10.2.3.2.JPQLIdentificationVariables .........................................................................107
10.2.3.3.JPQLRangeDeclarations...............................................................................108
10.2.3.4.JPQLPathExpressions ..................................................................................108
10.2.3.5.JPQLJoins ..................................................................................................110
10.2.3.5.1.JPQLInnerJoins(RelationshipJoins) ....................................................111
10.2.3.5.2.JPQLOuterJoins ...............................................................................111
10.2.3.5.3.JPQLFetchJoins ...............................................................................112
10.2.3.6.JPQLCollectionMemberDeclarations .............................................................112
10.2.3.7.JPQLFROMClauseandSQL.........................................................................113
10.2.3.8.JPQLPolymorphism .....................................................................................113
10.2.4.JPQLWHEREClause .............................................................................................113
10.2.5.JPQLConditionalExpressions...................................................................................114
10.2.5.1.JPQLLiterals...............................................................................................114
10.2.5.2.JPQLIdentificationVariables .........................................................................114
10.2.5.3.JPQLPathExpressions ..................................................................................115
10.2.5.4.JPQLInputParameters ..................................................................................115
10.2.5.4.1.JPQLPositionalParameters .................................................................115
10.2.5.4.2.JPQLNamedParameters .....................................................................115
10.2.5.5.JPQLConditionalExpressionComposition .......................................................115
10.2.5.6.JPQLOperatorsandOperatorPrecedence .........................................................116
10.2.5.7.JPQLComparisonExpressions........................................................................116
10.2.5.8.JPQLBetweenExpressions ............................................................................117
10.2.5.9.JPQLInExpressions .....................................................................................118
10.2.5.10.JPQLLikeExpressions ................................................................................118
10.2.5.11.JPQLNullComparisonExpressions ...............................................................119
10.2.5.12.JPQLEmptyCollectionComparisonExpressions .............................................119
10.2.5.13.JPQLCollectionMemberExpressions ............................................................120
10.2.5.14.JPQLExistsExpressions ..............................................................................120
10.2.5.15.JPQLAllorAnyExpressions ........................................................................121
10.2.5.16.JPQLSubqueries ........................................................................................121
10.2.6.JPQLScalarExpressions ..........................................................................................122
10.2.6.1.ArithmeticExpressions ..................................................................................122
10.2.6.2.String,Arithmetic,andDatetimeFunctionalExpressions .....................................122
10.2.6.2.1.JPQLStringFunctions ........................................................................123
10.2.6.2.2.JPQLArithmeticFunctions ..................................................................123
10.2.6.2.3.JPQLDatetimeFunctions ....................................................................124
10.2.6.3.CaseExpressions ..........................................................................................124
10.2.6.4.EntityTypeExpressions ................................................................................125
10.2.7.JPQLGROUPBY,HAVING ....................................................................................125
10.2.8.JPQLSELECTClause .............................................................................................126
10.2.8.1.JPQLResultTypeoftheSELECTClause .........................................................127
10.2.8.2.JPQLConstructorExpressions ........................................................................128
10.2.8.3.JPQLNullValuesintheQueryResult ..............................................................129
10.2.8.4.JPQLEmbeddablesintheQueryResult ............................................................129
10.2.8.5.JPQLAggregateFunctions .............................................................................129
10.2.8.5.1.JPQLAggregateExamples ..................................................................130
10.2.8.5.2.JPQLNumericExpressionsintheSELECTClause ..................................130
10.2.9.JPQLORDERBYClause.........................................................................................131
10.2.10.JPQLBulkUpdateandDelete .................................................................................132
10.2.11.JPQLNullValues..................................................................................................133
10.2.12.JPQLEqualityandComparisonSemantics .................................................................134
10.2.13.JPQLBNF ...........................................................................................................134
11.JPACriteria ................................................................................................................................138
11.1.ConstructingaCriteriaQuery ...............................................................................................138
11.2.ExecutingaCriteriaQuery ...................................................................................................139
vi
ApacheOpenJPA2.0User'sGuide
11.3.ExtensiontoCriteriaAPI ....................................................................................................139
11.4.GenerationofCanonicalMetaModelclasses ...........................................................................139
12.SQLQueries ...............................................................................................................................141
12.1.CreatingSQLQueries ........................................................................................................141
12.2.RetrievingPersistentObjectswithSQL .................................................................................141
13.MappingMetadata .......................................................................................................................143
13.1.Table...............................................................................................................................144
13.2.UniqueConstraints ............................................................................................................146
13.3.Column ...........................................................................................................................147
13.4.IdentityMapping ...............................................................................................................148
13.5.Generators........................................................................................................................150
13.5.1.SequenceGenerator .................................................................................................150
13.5.2.TableGenerator .......................................................................................................151
13.5.3.Example ................................................................................................................152
13.6.Inheritance .......................................................................................................................154
13.6.1.SingleTable ...........................................................................................................154
13.6.1.1.Advantages .................................................................................................155
13.6.1.2.Disadvantages ..............................................................................................155
13.6.2.Joined ...................................................................................................................155
13.6.2.1.Advantages .................................................................................................157
13.6.2.2.Disadvantages ..............................................................................................157
13.6.3.TablePerClass .......................................................................................................158
13.6.3.1.Advantages .................................................................................................159
13.6.3.2.Disadvantages ..............................................................................................159
13.6.4.PuttingitAllTogether .............................................................................................159
13.7.Discriminator....................................................................................................................162
13.8.FieldMapping ..................................................................................................................167
13.8.1.BasicMapping .......................................................................................................167
13.8.1.1.LOBs .........................................................................................................167
13.8.1.2.Enumerated .................................................................................................167
13.8.1.3.TemporalTypes ...........................................................................................168
13.8.1.4.TheUpdatedMappings ..................................................................................168
13.8.2.SecondaryTables ....................................................................................................173
13.8.3.EmbeddedMapping.................................................................................................174
13.8.4.DirectRelations ......................................................................................................177
13.8.5.JoinTable ..............................................................................................................179
13.8.6.BidirectionalMapping .............................................................................................182
13.8.7.MapMapping .........................................................................................................182
13.9.TheCompleteMappings .....................................................................................................183
14.Conclusion .................................................................................................................................192
3.ReferenceGuide ....................................................................................................................................193
1.Introduction ..................................................................................................................................200
1.1.IntendedAudience...............................................................................................................200
2.Configuration................................................................................................................................201
2.1.Introduction .......................................................................................................................201
2.2.RuntimeConfiguration .........................................................................................................201
2.3.CommandLineConfiguration ...............................................................................................201
2.3.1.CodeFormatting.......................................................................................................202
2.4.PluginConfiguration............................................................................................................203
2.5.OpenJPAProperties .............................................................................................................204
2.5.1.openjpa.AutoClear ....................................................................................................204
2.5.2.openjpa.AutoDetach ..................................................................................................204
2.5.3.openjpa.BrokerFactory...............................................................................................205
2.5.4.openjpa.BrokerImpl ..................................................................................................205
2.5.5.openjpa.Callbacks .....................................................................................................205
2.5.6.openjpa.ClassResolver ...............................................................................................205
2.5.7.openjpa.Compatibility ...............................................................................................206
2.5.8.openjpa.ConnectionDriverName ..................................................................................206
2.5.9.openjpa.Connection2DriverName ................................................................................206
vii
ApacheOpenJPA2.0User'sGuide
2.5.10.openjpa.ConnectionFactory .......................................................................................206
2.5.11.openjpa.ConnectionFactory2 .....................................................................................207
2.5.12.openjpa.ConnectionFactoryName ...............................................................................207
2.5.13.openjpa.ConnectionFactory2Name .............................................................................207
2.5.14.openjpa.ConnectionFactoryMode ...............................................................................207
2.5.15.openjpa.ConnectionFactoryProperties .........................................................................208
2.5.16.openjpa.ConnectionFactory2Properties........................................................................208
2.5.17.openjpa.ConnectionPassword ....................................................................................208
2.5.18.openjpa.Connection2Password ..................................................................................208
2.5.19.openjpa.ConnectionProperties ...................................................................................209
2.5.20.openjpa.Connection2Properties ..................................................................................209
2.5.21.openjpa.ConnectionURL ..........................................................................................209
2.5.22.openjpa.Connection2URL.........................................................................................209
2.5.23.openjpa.ConnectionUserName...................................................................................209
2.5.24.openjpa.Connection2UserName .................................................................................210
2.5.25.openjpa.ConnectionRetainMode ................................................................................210
2.5.26.openjpa.DataCache..................................................................................................210
2.5.27.openjpa.DataCacheManager ......................................................................................210
2.5.28.openjpa.DataCacheMode ..........................................................................................211
2.5.29.openjpa.DataCacheTimeout ......................................................................................211
2.5.30.openjpa.DetachState ................................................................................................211
2.5.31.openjpa.DynamicDataStructs.....................................................................................211
2.5.32.openjpa.FetchBatchSize ...........................................................................................212
2.5.33.openjpa.EncryptionProvider ......................................................................................212
2.5.34.openjpa.FetchGroups ...............................................................................................212
2.5.35.openjpa.FlushBeforeQueries .....................................................................................212
2.5.36.openjpa.IgnoreChanges ............................................................................................213
2.5.37.openjpa.Id..............................................................................................................213
2.5.38.openjpa.InitializeEagerly ..........................................................................................213
2.5.39.openjpa.InverseManager...........................................................................................213
2.5.40.openjpa.LockManager..............................................................................................214
2.5.41.openjpa.LockTimeout ..............................................................................................214
2.5.42.openjpa.Log ...........................................................................................................214
2.5.43.openjpa.ManagedRuntime ........................................................................................214
2.5.44.openjpa.Mapping ....................................................................................................215
2.5.45.openjpa.MaxFetchDepth...........................................................................................215
2.5.46.openjpa.MetaDataFactory .........................................................................................215
2.5.47.openjpa.MetaDataRepository.....................................................................................215
2.5.48.openjpa.Multithreaded .............................................................................................216
2.5.49.openjpa.Optimistic ..................................................................................................216
2.5.50.openjpa.OrphanedKeyAction.....................................................................................216
2.5.51.openjpa.NontransactionalRead...................................................................................216
2.5.52.openjpa.NontransactionalWrite ..................................................................................217
2.5.53.openjpa.ProxyManager ............................................................................................217
2.5.54.openjpa.QueryCache................................................................................................217
2.5.55.openjpa.QueryCompilationCache ...............................................................................217
2.5.56.openjpa.ReadLockLevel ...........................................................................................217
2.5.57.openjpa.RemoteCommitProvider................................................................................218
2.5.58.openjpa.RestoreState ...............................................................................................218
2.5.59.openjpa.RetainState .................................................................................................218
2.5.60.openjpa.RetryClassRegistration .................................................................................218
2.5.61.openjpa.RuntimeUnenhancedClasses ..........................................................................219
2.5.62.openjpa.DynamicEnhancementAgent ..........................................................................219
2.5.63.openjpa.SavepointManager .......................................................................................219
2.5.64.openjpa.Sequence....................................................................................................220
2.5.65.openjpa.Specification ...............................................................................................220
2.5.66.openjpa.TransactionMode .........................................................................................220
2.5.67.openjpa.WriteLockLevel ..........................................................................................220
2.6.OpenJPAJDBCProperties ....................................................................................................221
viii
ApacheOpenJPA2.0User'sGuide
2.6.1.openjpa.jdbc.ConnectionDecorators .............................................................................221
2.6.2.openjpa.jdbc.DBDictionary ........................................................................................221
2.6.3.openjpa.jdbc.DriverDataSource ...................................................................................221
2.6.4.openjpa.jdbc.EagerFetchMode ....................................................................................222
2.6.5.openjpa.jdbc.FetchDirection .......................................................................................222
2.6.6.openjpa.jdbc.JDBCListeners .......................................................................................222
2.6.7.openjpa.jdbc.LRSSize................................................................................................222
2.6.8.openjpa.jdbc.MappingDefaults ....................................................................................223
2.6.9.openjpa.jdbc.MappingFactory .....................................................................................223
2.6.10.openjpa.jdbc.QuerySQLCache ...................................................................................223
2.6.11.openjpa.jdbc.ResultSetType ......................................................................................223
2.6.12.openjpa.jdbc.Schema ...............................................................................................223
2.6.13.openjpa.jdbc.SchemaFactory .....................................................................................224
2.6.14.openjpa.jdbc.Schemas ..............................................................................................224
2.6.15.openjpa.jdbc.SQLFactory .........................................................................................224
2.6.16.openjpa.jdbc.SubclassFetchMode ...............................................................................224
2.6.17.openjpa.jdbc.SynchronizeMappings ............................................................................225
2.6.18.openjpa.jdbc.TransactionIsolation ..............................................................................225
2.6.19.openjpa.jdbc.UpdateManager ....................................................................................225
2.6.20.CompatibilitywithSpecification ................................................................................225
3.Logging .......................................................................................................................................227
3.1.LoggingChannels ...............................................................................................................227
3.2.OpenJPALogging ...............................................................................................................228
3.3.DisablingLogging ...............................................................................................................229
3.4.Log4J................................................................................................................................229
3.5.ApacheCommonsLogging ...................................................................................................230
3.5.1.JDKjava.util.logging.................................................................................................230
3.6.CustomLog .......................................................................................................................230
4.JDBC ..........................................................................................................................................232
4.1.UsingtheOpenJPADataSource .............................................................................................232
4.2.UsingaThird-PartyDataSource .............................................................................................233
4.2.1.ManagedandXADataSources ....................................................................................233
4.2.2.SettingtheDataSourceatruntime ................................................................................234
4.2.2.1.UsingdifferentdatasourcesforeachEntityManager ..............................................234
4.2.2.1.1.Benefits .............................................................................................234
4.2.2.1.2.Limitations .........................................................................................234
4.2.2.1.3.Errorhandling .....................................................................................235
4.3.RuntimeAccesstoDataSource ..............................................................................................235
4.4.DatabaseSupport ................................................................................................................236
4.4.1.DBDictionaryProperties ............................................................................................237
4.4.2.FirebirdDictionaryProperties ......................................................................................245
4.4.3.MySQLDictionaryProperties ......................................................................................246
4.4.4.OracleDictionaryProperties ........................................................................................246
4.4.5.SybaseDictionaryProperties .......................................................................................247
4.4.6.DelimitedIdentifiersSupport ......................................................................................247
4.5.SettingtheTransactionIsolation ............................................................................................247
4.6.SettingtheSQLJoinSyntax ..................................................................................................248
4.7.AccessingMultipleDatabases ...............................................................................................249
4.8.ConfiguringtheUseofJDBCConnections...............................................................................249
4.9.StatementBatching..............................................................................................................250
4.10.LargeResultSets...............................................................................................................252
4.11.DefaultSchema .................................................................................................................253
4.12.SchemaReflection .............................................................................................................254
4.12.1.SchemasList ..........................................................................................................254
4.12.2.SchemaFactory ......................................................................................................254
4.13.SchemaTool ....................................................................................................................255
4.14.XMLSchemaFormat .........................................................................................................258
5.PersistentClasses...........................................................................................................................261
5.1.PersistentClassList .............................................................................................................261
ix
ApacheOpenJPA2.0User'sGuide
5.2.Enhancement ......................................................................................................................261
5.2.1.EnhancingatBuildTime ............................................................................................262
5.2.2.EnhancingJPAEntitiesonDeployment ........................................................................263
5.2.3.EnhancingatRuntime................................................................................................263
5.2.4.EnhancingDynamicallyatRuntime .............................................................................264
5.2.5.OmittingtheOpenJPAenhancer ..................................................................................264
5.3.ManagedInterfaces .............................................................................................................265
5.4.ObjectIdentity ....................................................................................................................266
5.4.1.DatastoreIdentity .....................................................................................................266
5.4.2.EntitiesasIdentityFields ...........................................................................................267
5.4.3.ApplicationIdentityTool ...........................................................................................268
5.4.4.Autoassign/IdentityStrategyCaveats ..........................................................................269
5.5.ManagedInverses ...............................................................................................................270
5.6.PersistentFields ..................................................................................................................271
5.6.1.RestoringState .........................................................................................................271
5.6.2.TypingandOrdering .................................................................................................271
5.6.3.CalendarFieldsandTimeZones...................................................................................272
5.6.4.Proxies ...................................................................................................................272
5.6.4.1.SmartProxies ................................................................................................272
5.6.4.2.LargeResultSetProxies ..................................................................................272
5.6.4.3.CustomProxies..............................................................................................273
5.6.4.4.Serialization ..................................................................................................274
5.6.5.Externalization .........................................................................................................274
5.6.5.1.ExternalValues .............................................................................................277
5.7.FetchGroups ......................................................................................................................277
5.7.1.CustomFetchGroups ................................................................................................278
5.7.2.CustomFetchGroupConfiguration ..............................................................................279
5.7.3.Per-fieldFetchConfiguration ......................................................................................280
5.7.4.ImplementationNotes................................................................................................281
5.8.EagerFetching....................................................................................................................281
5.8.1.ConfiguringEagerFetching ........................................................................................282
5.8.2.EagerFetchingConsiderationsandLimitations ..............................................................283
6.Metadata ......................................................................................................................................284
6.1.MetadataFactory ................................................................................................................284
6.2.MetadataRepository ............................................................................................................285
6.3.AdditionalJPAMetadata ......................................................................................................285
6.3.1.DatastoreIdentity .....................................................................................................285
6.3.2.SurrogateVersion .....................................................................................................285
6.3.3.PersistentFieldValues...............................................................................................285
6.3.4.PersistentCollectionFields.........................................................................................286
6.3.5.PersistentMapFields ................................................................................................286
6.4.MetadataExtensions ............................................................................................................287
6.4.1.ClassExtensions.......................................................................................................287
6.4.1.1.FetchGroups .................................................................................................287
6.4.1.2.DataCache ...................................................................................................287
6.4.1.3.DetachedState ...............................................................................................287
6.4.2.FieldExtensions .......................................................................................................288
6.4.2.1.Dependent ....................................................................................................288
6.4.2.2.LoadFetchGroup ..........................................................................................288
6.4.2.3.LRS .............................................................................................................288
6.4.2.4.Inverse-Logical ..............................................................................................288
6.4.2.5.Read-Only ....................................................................................................288
6.4.2.6.Type ............................................................................................................289
6.4.2.7.Externalizer...................................................................................................289
6.4.2.8.Factory.........................................................................................................289
6.4.2.9.ExternalValues .............................................................................................289
6.4.3.Example .................................................................................................................290
7.Mapping ......................................................................................................................................291
7.1.ForwardMapping ................................................................................................................291
x