My second connection in sqlite is not work.

[artwaw]

@MhM93 But @Fuel is right - the code you posted has an error: you add second database but just afterwards change database name on the first one, not setting name on the second. And then you try to open it.

[MhM93]

thanks for both reply(@Fuel and @artwaw )
Sorry but I think I need more describe. could you please about it or write a little example code for me?
When I search I see these codes:
[https://forum.qt.io/topic/76810/use-two-or-more-sqlite-database-at-the-same-time/3]

db= QSqlDatabase::addDatabase("QSQLITE", "first_connection");
fallas= QSqlDatabase::addDatabase("QSQLITE", "second_connection");

after define connection I set the database name with the database name and path.
please write an example for me. sorry

[mrjj]

@MhM93 said in My second connection in sqlite is not work.:

hi
As @artwaw says

 bool DB::MergeData(QString dabkup)
 {
     try{
     daba2 = QSqlDatabase::addDatabase("QSQLITE","BkupDB");
     daba.setDatabaseName(dabkup); <<<<<<<<<<<< should be daba2

[MhM93]

thanks for answer and excuse me for silly mistake, I change it but again my app crash at this line
(I use qt4.8.6)

bool DB::MergeData(QString dabkup)
{

        qDebug("db backup start");
try{
        daba2 = QSqlDatabase::addDatabase("QSQLITE","BkupDB");   // = in this line
        }catch(...){
        qDebug()<<daba2.lastError().text();
    }
        qDebug("1");
        daba2.setDatabaseName(dabkup);
        qDebug("2");

        if(!daba2.open())
        {
            qDebug("db backup can not open");
            return false;
        }

[mrjj]

That is odd if it crashed there.
Do you allocate DB before you call MergeData ?
Please Show calling code.

[MhM93]

class PenDrive : public QWidget
{
    Q_OBJECT

public:
    explicit PenDrive(QWidget *parent = 0,SerialPort *finger=0);
    ~PenDrive();
    DB *database;

and:

void PenDrive::on_btnUploadUser_clicked()
{
    md=new MessageDialog(this);
    if(!CheckUSB())
    {
        md->error( tr("FAIL"), tr("Sorry.The USB is not detected at udisk0."));
        return;
    }
    QFile::copy("/media/usb/IODBbkup", "IODBbkup");
    qDebug("before call database");
    if(database->MergeData("IODBbkup")){
        md->success(tr("Step one"),tr("Successfully finished step one, \n Please wait to write data on sensor."));
        fdb->WriteFinger(NULL);
    }
    else
        md->error(tr("Step one"),tr("Error occured in step one."));

}

and merg code:

bool DB::MergeData(QString dabkup)
{
    try{
        qDebug("db backup start");
        
        daba2 = QSqlDatabase::addDatabase("QSQLITE","BkupDB");//not dbConnection
        qDebug("1");
        daba2.setDatabaseName(dabkup);
        qDebug("2");
    
        if(!daba2.open())
        {
            qDebug("db backup can not open");
            return false;
        }
    
        qDebug("db backup is open");
        //-----------------------------------------------------------
        QSqlQuery q("select * from userinfo;",QSqlDatabase::database("BkupDB"));
        QSqlQueryModel *lst=new QSqlQueryModel();
        lst->setQuery(q);
        int pid=0;
        int id=0;
        bool admin=false,active=false;
    
        //insert userinfo at first step
        for(int i = 0; i < lst->rowCount(); ++i)
        {
            pid=lst->record(i).value(1).toInt();
            admin=lst->record(i).value(2).toInt();
            active=lst->record(i).value(3).toInt();
            q.prepare("select count(UI_PID) from userinfo where UI_PID=:pid;");
            q.bindValue(0,pid);
            //insert into userinfo main database
            //from backup database
            qDebug()<<"pid:"<<pid<<"  admin:"<<admin<<"  active:"<<active<<"  ";
            if(q.exec())
                while(q.next())
                {
                    if(q.value(0).toInt()==0)
                    {
                        id=GetMaxUserID(1).toInt();
                        IE_userinfo(id,pid,admin,active);
                    }
                }
        }
        MergeAuthenticate();
        daba2.close();
    }catch(...){
        qDebug()<<daba2.lastError().text();
    }
    qDebug()<<daba2.lastError().text();

return false;
}

output is :

before call database
db backup start

[mrjj]

@MhM93 said in My second connection in sqlite is not work.:

DB *database;

Do you new this ?
DB *database = new DB;

Else you crash if u call functions on it.

[MhM93]

@mrjj said in My second connection in sqlite is not work.:

That is odd if it crashed there.
Do you allocate DB before you call MergeData ?
Please Show calling code.

really thanks, again silly mistake. I add new and it is true. but in whole of my app does not use new and all of them worked.
could you explain it to me?(So sorry)

[mrjj]

@MhM93

Hi
If you declare something as pointer ( with *) you need to call new
to have it be an actual object. else it just points to random location in memory.

So
DB My1; // fine. its actual object, not pointer

DB *My1; // just pointer. Points to nothing valid yet

My1= new DB; // now it points to a real object

[MhM93]

thank you :)