Driver not loaded QSQlite when I give connection name

philxxx609

Hello,

When I use QSQlite with

databaseManager::databaseManager()
{
db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(db_URL);
}
void databaseManager::dbinitmagUrl()
{
    {
        db.open();
        QSqlQuery query(db);
        if(!query.exec("CREATE TABLE IF NOT EXISTS dbMagasin_log (ligne_id INTEGER PRIMARY KEY AUTOINCREMENT, url TEXT)"))
        {
            qDebug() << "query return error at line:"<<QString::number(__LINE__)<<query.lastError().text();
        }
    }
    QSqlDatabase::removeDatabase("QSQLITE");
}

My app is working.

But when I try to use connection name, I receive error

QSqlDatabasePrivate::removeDatabase: connection 'test' is still in use, all queries will cease to work.
QSqlQuery::exec: database not open
"query return null at line:561" QSqlError("", "Driver not loaded", "Driver not loaded")

databaseManager::databaseManager()
{
db = QSqlDatabase::addDatabase("QSQLITE", "test");
db.setDatabaseName(db_URL);
}
void databaseManager::dbinitmagUrl()
{
    {
        db.open();
        QSqlQuery query(QSqlDatabase::database("test"));
        if(!query.exec("CREATE TABLE IF NOT EXISTS dbMagasin_log (ligne_id INTEGER PRIMARY KEY AUTOINCREMENT, url TEXT)"))
        {
            qDebug() << "query return error at line:"<<QString::number(__LINE__)<<query.lastError().text();
        }
    }
    QSqlDatabase::removeDatabase("test");
}

Could you help me?

Thanks a lot

jsulm

@philxxx609 said in Driver not loaded QSQlite when I give connection name:

db = QSqlDatabase::addDatabase("QSQLITE", "test");
db.setDatabaseName(db_URL);

Do NOT store QSqlDatabase instances in variables!
This is explained in the documentation.

philxxx609

I just saw that, thank you.

Do you know the best practice to use sqlite in multi users connection?

jsulm

@philxxx609 said in Driver not loaded QSQlite when I give connection name:

Do you know the best practice to use sqlite in multi users connection?

Not sure what you mean with "best practice".
SQlite supports parallel accesses, but if one process is writing the DB will be locked until writing has finished.

philxxx609

@jsulm yes that is my problem, so I can not do any thing to avoid the app blocked until the other access finish to write on it

jsulm

@philxxx609 I'm not sure your app will block. Never used SQLitein such configuration. Try it out and see what happens, maybe your query will fail as long as the database is blocken, in this case your app will not be blocked.

philxxx609

@jsulm yes it 's what is happening

jsulm

@philxxx609 Then SQLite is not the right database for your use case