unable to open sqlite3 database in QT - linux

Question

I am in the beginning phase of both sqlite, as well as QT.
There are various examples under QtSDK IDE for sqlite database. This is an excerpt from one of the examples :
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(":memory:");
if (!db.open()) {
QMessageBox::critical(0, qApp->tr("Cannot open database"),
qApp->tr("Unable to establish a database connection.\n"
"This example needs SQLite support. Please read "
"the Qt SQL driver documentation for information how "
"to build it.\n\n"
"Click Cancel to exit."), QMessageBox::Cancel);
return false;
}
This works just fine. but if I try to replace ":memory:" with an actual sqlite3 database file,...
void MainWindow::on_pushButton_5_clicked()
{
QSqlQuery query;
accounts_db = new QSqlDatabase();
*accounts_db = QSqlDatabase::addDatabase("QSQLITE"); perror("");
accounts_db->setDatabaseName("/home/aditya/test.db.sqlite");
QSqlError *a = new QSqlError();
*a = accounts_db->lastError();
perror(a->text().toLatin1());
if (!accounts_db->open()) {
perror("database open error :");
QMessageBox::critical(0,qApp->tr("db.open\n"),a->text(),QMessageBox::Cancel);
goto end; // quit if not successful
}
if ( !accounts_db->isOpen() ) {
perror("database is not open");
}
query.exec("select accno,branchcode,fname,lname,curbalance,accdate from accounts");
while(query.next()) {
QString str = query.value(0).toString();
std::cerr << qPrintable(str) << std::endl;
}
end:
;
}
...then I am not so lucky. Not sure exactly how lastError() works, but tried it anyway. I am getting these errors...
No such file or directory
: Invalid argument
QSqlQuery::exec: database not open
I have tried changing the permissions n'all on the concerned files and folders as suggested on different forums, but to no results. Just a note, I am working on Ubuntu Linux (...if that matters), I have also tested this test.db database file with the sqlite3 command line program, that works flawless.
Any guidance is appreciated...thanks.
EDIT:
Very sorry that I completely forgot to explain what the error is... :|

Answer 1

Created a brand new database, and it works !!!
not clear why it was not working before though... I definitely need to study more.
Anyway, thanks a lot ppl :) .