Ok, maybe you can give me a pointer on what I'm doing wrong then. My code is
structured like the following:
bool openDatabase(){
QSqlDatabase db=QSqlDatabase::addDatabase('QSQLITE');
db.setDatabaseName(<path_to_my_database_file>);
return db.open();
}
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
...
<various initialization code>
...
bool dbOpen=openDatabase();
...
<more initilization>
return a.exec();
}
And if I put a breakpoint at any point after the call to OpenDatabase, the
database is open - it does not close, even though that QSqlDatabase object went
out of scope. At no point in my application do I keep a copy of QSqlDatabase
around in any of my classes - every call to QSqlDatabase is as a function local
member, and as such goes out of scope (thereby theoretically calling the
destructor) as soon as the function exits.
So what am I missing here?
-----------------------------------------------
Israel Brewster
Systems Analyst II
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7293
-----------------------------------------------
[cid:8f9ccd5b-5a65-4794-b193-af4863e7f7aa@flyravn.com]
[cid:a01d4aae-c628-436a-a1af-b0b73bd6c7bd@flyravn.com]
On Aug 21, 2018, at 12:31 PM, Roland Hughes
<rol...@logikalsolutions.com<mailto:rol...@logikalsolutions.com>> wrote:
Why are you creating yet another class instead of properly structuring your
application?
Take a gander at
http://www.logikalsolutions.com/wordpress/information-technology/qt-and-usb-pt-4/
for some ideas. You probably also want to find a copy of this book
http://www.theminimumyouneedtoknow.com/qt_book.html
Most importantly you need to read the fine manual.
http://doc.qt.io/qt-5/qsqldatabase.html#dtor.QSqlDatabase
QSqlDatabase::~QSqlDatabase()
Destroys the object and frees any allocated resources.
Note: When the last connection is destroyed, the destructor implicitly calls
close<http://doc.qt.io/qt-5/qsqldatabase.html#close>() to release the database
connection.
See also close<http://doc.qt.io/qt-5/qsqldatabase.html#close>().
If your database is open for the life of the application then the application
has a failed architecture. Database connections aren't supposed to have actual
life spans.
On 08/21/2018 03:08 PM, Israel Brewster wrote:
Ideally, what I'd have is a system where you set up the connection, and then it
automatically opens/closes the connection when needed (i.e. when doing a
SELECT, INSERT, UPDATE, etc). With my app, this would generally only be for a)
periodic updates or b) in direct response to user input, so most of the time
the connection could remain closed. To the best of my knowledge (correct me if
I am wrong), this is not possible with the existing QSqlDatabase/ QSQLITE
database driver classes.
--
Roland Hughes, President
Logikal Solutions
(630) 205-1593
http://www.theminimumyouneedtoknow.com<http://www.theminimumyouneedtoknow.com/>
http://www.infiniteexposure.net<http://www.infiniteexposure.net/>
http://www.johnsmith-book.com<http://www.johnsmith-book.com/>
http://www.logikalblog.com<http://www.logikalblog.com/>
http://www.interestingauthors.com/blog
http://lesedi.us<http://lesedi.us/>
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