still some problems on update databases using QDataWidgetMapper

i am using the Qt 4.6.2 and i can't update the databases,but after i inserted ,i can update the new row into the dabasese;
i have asked the question before,but nobody would liket to help me, i am confused by this question for a long time ,anyone can help me ?plz!

Code:

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void WellDataManage::loadWellData(QString projectAddress)
{
	QString address=projectAddress;
	address+="//";
	address+="Data";
	address+="//";
	address+="SystemData";
	address+=".db3";
 
	if (!QFile::exists(address))
	{
		QMessageBox::information(this,tr("Information"),tr("There is something wrong with the wells databases"),QMessageBox::Ok,QMessageBox::Ok);
	}
 
	QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
	db.setDatabaseName(address);	
	db.open();
 
 
 
 
	welldatamodel = new QSqlTableModel;
 
	welldatamodel->setEditStrategy(QSqlTableModel::OnManualSubmit);
	welldatamodel->setTable("wells");
	welldatamodel->setSort(0,Qt::AscendingOrder);
	welldatamodel->select();
 
	//set Comobox model
 
 
	//wellTypeComoBox->setModel(welldatamodel);
	//wellTypeComoBox->setModelColumn(welldatamodel->fieldIndex("welltype"));
 
	//set header name
	welldatamodel->setHeaderData(0,Qt::Horizontal,tr("Name"));
	welldatamodel->setHeaderData(1,Qt::Horizontal,tr("Group"));
	welldatamodel->setHeaderData(2,Qt::Horizontal,tr("X"));
	welldatamodel->setHeaderData(3,Qt::Horizontal,tr("Y"));
	welldatamodel->setHeaderData(4,Qt::Horizontal,tr("Type"));
	welldatamodel->setHeaderData(5,Qt::Horizontal,tr("Production"));
	welldatamodel->setHeaderData(6,Qt::Horizontal,tr("Depth"));
	welldatamodel->setHeaderData(7,Qt::Horizontal,tr("BeginDepth"));
	welldatamodel->setHeaderData(8,Qt::Horizontal,tr("EndDepth"));
	welldatamodel->setHeaderData(9,Qt::Horizontal,tr("Altitude"));
 
 
 
	welldatamodel->removeColumn(0);
 
	wellTableView->setModel(welldatamodel);
	wellTableView->setSelectionBehavior(QAbstractItemView::SelectRows);
	wellTableView->resizeRowsToContents();
 
 
	welldatamapper=new QDataWidgetMapper(this);
 
	welldatamapper->setModel(welldatamodel);
	welldatamapper->setSubmitPolicy(QDataWidgetMapper::AutoSubmit);
	//welldatamapper->setItemDelegate(new QSqlRelationalDelegate(welldatamapper));
 
 
	welldatamapper->addMapping(wellNameEdit,0);
	welldatamapper->addMapping(wellGroupEdit,1);
	welldatamapper->addMapping(wellXPositionEdit,2);
	welldatamapper->addMapping(wellYPositionEdit,3);
	welldatamapper->addMapping(wellTypeComoBox,4);
	welldatamapper->addMapping(wellProductionEdit,5);
 
	welldatamapper->addMapping(wellBeginDepthEdit,7);
	welldatamapper->addMapping(wellEndDepthEdit,8);
	welldatamapper->addMapping(wellAltitudeEdit,9);
 
 
 
	//create connect of the buttons
	welldatamapper->toFirst();//初始化时选择选择第一行
	connect(wellTableView->selectionModel(),SIGNAL(currentRowChanged(QModelIndex, QModelIndex)),welldatamapper,SLOT(setCurrentModelIndex(QModelIndex) ));
	connect(welldatamapper,SIGNAL(currentIndexChanged(int)),wellTableView,SLOT(selectRow (int)));
 
 
 
	connect(firstAction,SIGNAL(triggered()),welldatamapper,SLOT(toFirst()));
	connect(lastAction,SIGNAL(triggered()),welldatamapper,SLOT(toLast()));
	connect(previousAction,SIGNAL(triggered()),welldatamapper,SLOT(toPrevious()));
	connect(nextAction,SIGNAL(triggered()),welldatamapper,SLOT(toNext()));
	connect(newAction,SIGNAL(triggered()),this,SLOT(addWellRecord()));
	connect(deleteAction,SIGNAL(triggered()),this,SLOT(deleteWellRecord()));
	connect(updateAction,SIGNAL(triggered()),this,SLOT(updateWellRecord()));	
 
 
}
 
void WellDataManage::addWellRecord()
{
 
	int row=welldatamapper->currentIndex();
	if (row==-1)
	{
		row=0;
	}
	welldatamapper->submit();
	welldatamodel->insertRow(row);
	welldatamapper->setCurrentIndex(row);
 
 
	wellNameEdit->clear();
	wellGroupEdit->clear();
	wellXPositionEdit->clear();
	wellYPositionEdit->clear();
	wellBeginDepthEdit->clear();
	wellEndDepthEdit->clear();
	wellProductionEdit->clear();
	wellTypeComoBox->clear();
	wellNameEdit->setFocus();
}
 
 
 
 
void WellDataManage::deleteWellRecord()
{
	int row=welldatamapper->currentIndex();
	welldatamodel->removeRow(row);
	welldatamapper->submit();
	welldatamodel->submit();
	welldatamodel->submitAll();
 
	//welldatamapper->setCurrentIndex(QMIN(row,welldatamodel->rowCount()-1));
}
 
void WellDataManage::updateWellRecord()
{
    welldatamapper->submit();
	welldatamodel->submit();
	welldatamodel->submitAll();	
 
}

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someone help me ,plz:)

can you show your database structure?

the sql script of create databases like this:

Code:

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CREATE TABLE [wells] ([id] INTEGER PRIMARY KEY,[wellnames] NVARCHAR, [wellgroup] NVARCHAR,[XPosition] DOUBLE, [YPosition] DOUBLE,[welltype] CHAR, [production(m3)] DOUBLE,[depth] DOUBLE, [beginDetpth] DOUBLE, [endDepth] CHAR,[altitude] DOUBLE);

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In your void WellManage::loadWellData(QString projectAddress) function, why do you remove the first column?

Code:

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welldatamodel->removeColumn(0);

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Then, how do you set the first column data?

because i don't want to show this colum to the user,

anyone can help me ? i have confessed by this proble for one month!

If you want to hide a specific column, use

Code:

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tableView->setColumnHidden(column_num, true);

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.

When i remove the first column using

Code:

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model->removeColumn(0);

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,
i can't update or delete the record and this error occurs

Code:

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QSqlQuery::value: not positioned on a valid record

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.