如何刪除在nhibernate中級聯的集合？

Question

我有這個映射

public class CountryMapping : ClassMap<Country> 
    { 
     public CountryMapping() 
     { 
      Id(x => x.Id).GeneratedBy.GuidComb(); 
      Map(x => x.Name).Not.Nullable().NvarcharWithMaxSize(); 
      HasMany(x => x.Cards).Cascade.Delete().Inverse(); 
     } 
    } 

     public class CardMapping : ClassMap<Card> 
    { 
     public CardMapping() 
     { 
      Id(x => x.Id).GeneratedBy.GuidComb(); 
      Map(x => x.Name).Not.Nullable().NvarcharWithMaxSize(); ; 
      References(x => x.Country).Not.Nullable(); 
      HasMany(x => x.RewardTiers).Cascade.All(); 
     } 
    } 

現在我想刪除一個國家。如果你刪除一個國家，所有的卡片都應該被刪除。它應該刪除所有的獎勵。

nhibernateRepo.Load<Country>(countryId); 
nhibernateRepo.Delete<Country>(country); 
unitOfWork.Commit(); 

當我做到這一點。我收到以下錯誤。

NHibernate.Exceptions.GenericADOException was caught 
    Message=could not delete collection: [Domain.Card.RewardTiers#7abaade7-4653-456f-8840-9fc700fa949b][SQL: UPDATE [RewardTier] SET Card_id = null WHERE Card_id = @p0] 
    Source=NHibernate 
    SqlString=UPDATE [RewardTier] SET Card_id = null WHERE Card_id = @p0 
    StackTrace: 
     at NHibernate.Persister.Collection.AbstractCollectionPersister.Remove(Object id, ISessionImplementor session) 
     at NHibernate.Action.CollectionRemoveAction.Execute() 
     at NHibernate.Engine.ActionQueue.Execute(IExecutable executable) 
     at NHibernate.Engine.ActionQueue.ExecuteActions(IList list) 
     at NHibernate.Engine.ActionQueue.ExecuteActions() 
     at NHibernate.Event.Default.AbstractFlushingEventListener.PerformExecutions(IEventSource session) 
     at NHibernate.Event.Default.DefaultFlushEventListener.OnFlush(FlushEvent event) 
     at NHibernate.Impl.SessionImpl.Flush() 
     at NHibernate.Transaction.AdoTransaction.Commit() 
     at CCRecomendator.Framework.Data.UnitOfWork.Commit() in UnitOfWork.cs:line 52 
     at CCRecomendator.Framework.Services.CountryService.DeleteCountry(Guid countryId) in CountryService.cs:line 157 
    InnerException: System.Data.SqlClient.SqlException 
     Message=Cannot insert the value NULL into column 'Card_id', table 'cc.dbo.RewardTier'; column does not allow nulls. UPDATE fails. 
The statement has been terminated. 
     Source=.Net SqlClient Data Provider 
     ErrorCode=-2146232060 
     Class=16 
     LineNumber=1 
     Number=515 
     Procedure="" 
     Server=(local) 
     State=2 
     StackTrace: 
      at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) 
      at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) 
      at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning() 
      at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) 
      at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) 
      at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) 
      at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) 
      at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) 
      at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() 
      at NHibernate.AdoNet.AbstractBatcher.ExecuteNonQuery(IDbCommand cmd) 
      at NHibernate.Persister.Collection.AbstractCollectionPersister.Remove(Object id, ISessionImplementor session) 
     InnerException: 

爲什麼在發生刪除時試圖進行更新？

Answer 1

它試圖進行更新，因爲它認爲Card是國家 - >卡片協會的「所有者」，所以當一個國家被刪除時，NH認爲它需要空國家參考。這是由逆映射修改器引起的。根據該文件爲Inverse：

逆這個實體的所有權。使 關係的另一端負責保存。

嘗試從HasMany(x => x.Cards).Cascade.Delete().Inverse();