Nullable Property throws errors when Null in NHibernate
I have a property defined in my HBM file like this:
<property name="OwnerId" column="OwnerID" type="System.Int32" not-null="false" />
It is also defined as a nullable field in the database. If the record in the DB has the OwnerID column set to an integer, this object is loaded correctly by NHibernate. But if the entry is null, NHibernate bombs with seemingly random errors, including:
1) Column name "ModuleAnchorID" appears more than once in the list of result columns:
[SqlException (0x80131904): Column name 'ModuleAnchorID' appears more than once in the result column list.]
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +925466
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +800118
System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +186
System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +1932
System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) +149
System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +1005
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +132
System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) +149
System.Data.SqlClient.SqlCommand.ExecuteNonQuery() +135
NHibernate.Impl.NonBatchingBatcher.AddToBatch(IExpectation expectation) +35
NHibernate.Persister.Entity.AbstractEntityPersister.Update(Object id, Object[] fields, Object[] oldFields, Boolean[] includeProperty, Int32 j, Object oldVersion, Object obj, SqlCommandInfo sql, ISessionImplementor session) +1055
2) the null-null property refers to a null or transient value:
[PropertyValueException: not-null property references a null or transient value:]
NHibernate.Impl.SessionImpl.CheckNullability(Object[] values, IEntityPersister persister, Boolean isUpdate) +224
NHibernate.Impl.SessionImpl.FlushEntity(Object obj, EntityEntry entry) +1019
NHibernate.Impl.SessionImpl.FlushEntities() +182
NHibernate.Impl.SessionImpl.FlushEverything() +90
NHibernate.Impl.SessionImpl.AutoFlushIfRequired(ISet querySpaces) +64
NHibernate.Impl.SessionImpl.Find(CriteriaImpl criteria, IList results) +217
NHibernate.Impl.SessionImpl.Find(CriteriaImpl criteria) +42
NHibernate.Impl.CriteriaImpl.List() +29
Is OwnerID a reserved field name that obfuscates NHibernate in some way?
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Can you change the type of the object to Nullable (int?). OwnerId is not a reserved keyword. If you think about how you can map DB null to Int32. Value objects do not support null semantics, so you really need to use a nullable type.
Regarding the ModuleAnchorId, I recommend that you enable sql mapping and then submit the sql to the nhibernate usergroup on google. NHibernate developers are paying attention to this group.
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