UI use QSqltablemodel, the other thread use QSqlQuery to insert , return false

[5free]

Hi,

I am struggling with the multi-thread QSQLITE, the GUI thread is refresh the display through QSqlTableModel, the other thread insert data to sqlite cyclically.
but the problem is, once GUI thread use QSqlTableModel::select(), the other thread could not insert , and return : QSqlError("5", "Unable to fetch row", "database is locked")

what could I do next step to resolve the problem?

my codes like below:

this is the GUI thread

processDisplayDB =new QSqlDatabase(QSqlDatabase::addDatabase("QSQLITE","processDisplaydb"));
        processDisplayDB->setDatabaseName("databases/ProductionData.s3db");
        if(!processDisplayDB->open()){
            qDebug()<<"Could not open file!"<<endl;
            return;
        }else{
             qDebug()<<"Open file: "<<processDisplayDB->databaseName()<<" sucessfully!"<<endl;
        }
        modelProcessDisplay = new QSqlTableModel(ui->tableViewProcessDisplay,*processDisplayDB);
        modelProcessDisplay->setTable("processtable");

processDisplayDB =new QSqlDatabase(QSqlDatabase::addDatabase("QSQLITE","processDisplaydb"));
        processDisplayDB->setDatabaseName("databases/ProductionData.s3db");
        if(!processDisplayDB->open()){
            qDebug()<<"Could not open file!"<<endl;
            return;
        }else{
             qDebug()<<"Open file: "<<processDisplayDB->databaseName()<<" sucessfully!"<<endl;
        }
        modelProcessDisplay = new QSqlTableModel(ui->tableViewProcessDisplay,*processDisplayDB);
        modelProcessDisplay->setTable("processtable");

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and through a timer to refresh the display

connect(&cylicTimerProcessDisplay,&QTimer::timeout,this,&MainWindow::processDisplayUpdate_cylic);

connect(&cylicTimerProcessDisplay,&QTimer::timeout,this,&MainWindow::processDisplayUpdate_cylic);

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void MainWindow::processDisplayUpdate_cylic()
    {
      modelProcessDisplay->select();
    }

void MainWindow::processDisplayUpdate_cylic()
    {
      modelProcessDisplay->select();
    }

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the other thread is like this

processDB = new QSqlDatabase(QSqlDatabase::addDatabase("QSQLITE","processDB"));
        processDB->setDatabaseName("databases/ProductionData.s3db");
        if(!processDB->open()){
            qDebug()<<"Could not open file!"<<endl;
            return;
        }else{
             qDebug()<<"Open file: "<<processDB->databaseName()<<" sucessfully!"<<endl;
        }

processDB = new QSqlDatabase(QSqlDatabase::addDatabase("QSQLITE","processDB"));
        processDB->setDatabaseName("databases/ProductionData.s3db");
        if(!processDB->open()){
            qDebug()<<"Could not open file!"<<endl;
            return;
        }else{
             qDebug()<<"Open file: "<<processDB->databaseName()<<" sucessfully!"<<endl;
        }

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and write data cyclic

QSqlQuery query(*processDB);
        qDebug()<<"insert processtable prepare : "
               <<query.prepare("INSERT INTO processtable(SerialNo) "
                               "VALUES(:SerialNo)");
        query.bindValue(":SerialNo",currentSerialNo);
        qDebug()<<"insert processtable: "<<query.exec();

QSqlQuery query(*processDB);
        qDebug()<<"insert processtable prepare : "
               <<query.prepare("INSERT INTO processtable(SerialNo) "
                               "VALUES(:SerialNo)");
        query.bindValue(":SerialNo",currentSerialNo);
        qDebug()<<"insert processtable: "<<query.exec();

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but the query.exec() return false, once the GUI thread excuted the select(), the return error is : QSqlError("5", "Unable to fetch row", "database is locked")

[ChrisW67]

...and the error returned to the inserting code?
Ensure the insert code is wrapped in a transaction() that is finished with either commit() or rollback()