Why QSqlDatabase::open() returns open?

[gboelter]

By using the setDatabaseName() function and set your database name; then call open() and you will see if you have opened correctly your database.

That's what I'm doing normally. But in this case I get the name of the dataBase from another database using a getter called getDatabase(). And with open() alone there is a high risk, that getDatabase() will return an empty string but open() will return true.

Ok, I can change my getter, but have expected, that Qt4 can do that alone.

[vfernandez]

Then you can just make sure dbName is not empty.

QSqlDatabase db = QSqlDatabase::addDatabase(...);
 
QString dbName = getDatabase();
if(dbName.isEmpty()) {
  emit error();
  return;
}
 
db.setDatabaseName(dbName);
db.connect();

QSqlDatabase db = QSqlDatabase::addDatabase(...);

QString dbName = getDatabase();
if(dbName.isEmpty()) {
  emit error();
  return;
}

db.setDatabaseName(dbName);
db.connect();

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[Lykurg]

Ok, I can change my getter, but have expected, that Qt4 can do that alone.

But if Qt would return false if the database is empty, then you couldn't connect only to the server with Qt. So, Qt works as one expect it. And for your case simply check re returned value of your function if it is empty as vfernandez has suggested.