QSqlQuery::value: not positioned on a valid record

[mrjj]

hi and welcome

Does the exact same code work when you load it from
hard drive ?

Its possible to open it in READONLY mode.
https://www.sqlite.org/c3ref/open.html
SQLITE_OPEN_READONLY
maybe you can do that in Qt too ?
(since as resource, its read only)

Found it:
db.setConnectOptions(QLatin1String("QSQLITE_OPEN_READONLY"));

https://bugreports.qt.io/browse/QTBUG-34920

[Ocascante]

Hi,
Yes, the same code works ok loading from hard disk. I test this code:
QSqlDatabase db;
db.setConnectOptions(QLatin1String("QSQLITE_OPEN_READONLY"));
db = QSqlDatabase::addDatabase("QSQLITE");
.....

Got same error

[mrjj]

@Ocascante
Hmm. Ok.
So it seems it don't like the db to be in a resource.
just to be 100% sure can you swap the lines?
QSqlDatabase db;
db = QSqlDatabase::addDatabase("QSQLITE");
db.setConnectOptions(QLatin1String("QSQLITE_OPEN_READONLY"));

.....

[Ocascante]

@mrjj I did it, same error!!

The code:

if(db.open()){
qDebug()<<"DATABASE OPEN";
query.exec("SELECT COUNT(*) FROM Hours");
....

Debug:

DATABASE OPEN
QSqlQuery::exec: database not open

[mrjj]

@Ocascante
Ok. so if same code works from hard drive, then it don't like ressources

https://forum.qt.io/topic/3949/sqlite-database-in-project

[Ocascante]

@mrjj Do you know any other way to include a database ( not to create ) in a project?
Thanks again!

[mrjj]

@Ocascante
well you could have it as resource and then write it out to file.
Then use the file.
Since you will need tons of DLLS too and such. its it not an option to
just include the db file?

[Ocascante]

@mrjj I did a test including a .csv resource , and then creating the table from this file. The problem is that 1500 records with 5 fields each one, takes more than 5 minutes loading to the database.

[mrjj]

@Ocascante
ok. and the reason you want it in the resource, is to protect it from fiddling ?

[SGaist]

Hi and welcome to devnet,

As @mrjj suggested, SQLite can't read database from Qt's resources, it's not written for that. However you can copy the database from your executable to the hard drive in one of the writable location provide provided by QStandardPaths

[Ocascante]

@mrjj There are two main reasons:

I want to build this application for android
and to protect it from fiddling.

[mcosta]

Hi,

you could embed a database dump and import it each time you start the application

[Ocascante]

@mcosta Hi,

I need import a new database file, only when there is an application update.

[Ocascante]

@Ocascante Hi, thanks for your help. I found the solution using qt resources to pack my sqlite database, the code:

QString addin_path =QStandardPaths::writableLocation(QStandardPaths::DataLocation);

QDir dir(addin_path);
if (!dir.exists())
    dir.mkpath(addin_path);
if (!dir.exists("addins"))
    dir.mkdir("addins");

dir.cd("addins");
addin_path = dir.absoluteFilePath("Rutasdb.sqlite");
qDebug()<<addin_path;

if (QFile::exists(addin_path))
    QFile::remove(addin_path);

QFile::copy(":/Rutasdb.sqlite", addin_path);

QSqlDatabase db;
db = QSqlDatabase::addDatabase("QSQLITE");
db.setConnectOptions(QLatin1String("QSQLITE_OPEN_READONLY"));

db.setDatabaseName(addin_path);
db.open();

Now i can upgrade the data every update.

Thanks again.