code: public int isNullable( int index ) throws OdaException
  	{
  		int type =  getColumnType( index );
  		if (sqlTypesMayBeNull.containsKey(type)){
  			return IResultSetMetaData.columnNullable;
  		}else{
  			return IResultSetMetaData.columnNoNulls;
  		}
  	}
docs: /*
  @see org.eclipse.datatools.connectivity.oda.IResultSetMetaData#isNullable(int)