Qt cannot connect to mysql, libqsqlmysql.dylib is not loading. HELP please.

abdol

Hi every one. This is my first post in this forum. I hope someone gives me some clues on how to resolve this issue.
I have gone through the documentation of building Qt and mysql, I also built the the drivers successfully but after installing them in the correct directory I can't see mysql driver in the out put string.

please see this link for further info:
http://www.qtcentre.org/threads/42394-can-not-connect-to-mysql-using-Qt-help-me-please

I have built the qt libraries and qt creator on my computer (using the method recommended in the Qt documentation, qmake, make, ...)

I also compiled mysql on my computer using mysql online documentation:

http://doc.qt.nokia.com/latest/sql-driver.html#qmysql

I managed to create libqsqlmysql.dylib and libqsqlmysql_debug.dylib and installed them in

/usr/local/Trolltech/Qt-4.7.3/plugins/sqldrivers

where my qt is installed. when i run the following code
@
#include <QtCore/QCoreApplication>
#include <QtSql>
#include <QtDebug>

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QSqlDatabase * db = new QSqlDatabase;

qDebug() << db->drivers();
qDebug() << QCoreApplication::libraryPaths();
return 1;
}@

i only get
("QSQLITE", "QODBC3", "QODBC")

why mysql's driver is not loading?

These three drivers in addition to the one that I installed are all there. Here is ls result:

dhcp-85-5:sqldrivers ***$ ls
libqsqlite.dylib libqsqlmysql_debug.dylib
libqsqlite_debug.dylib libqsqlodbc.dylib
libqsqlmysql.dylib libqsqlodbc_debug.dylib

I used otool before and this is what i got:
libqsqlmysql.dylib:
libqsqlmysql.dylib (compatibility version 0.0.0, current version 0.0.0)
libmysqlclient.18.dylib (compatibility version 18.0.0, current version 18.0.0)
/usr/local/Trolltech/Qt-4.7.3/lib/QtSql.framework/Versions/4/QtSql (compatibility version 4.7.0, current version 4.7.3)
/usr/local/Trolltech/Qt-4.7.3/lib/QtCore.framework/Versions/4/QtCore (compatibility version 4.7.0, current version 4.7.3)
/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
/usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 830.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.10)

i also tried echo $DYLD_LIBRARY_PATH and i get empty string. Would you please tell me what value this should be set to?

goetz

Just a guess: libmysqlclient.18.dylib cannot be found. Add the path to the directory containing libmysqlclient.18.dylib to DYLD_LIBRARY_PATH.

abdol

Thank you Volker,
My question is I don't know where to go and set DYLD_LIBRARY_PATH.
When I use terminal (bash) in mac it only sets it for the current terminal and when I close it every thing is gone.

There should be a file somewhere so that I can edit it for the user or globally but i don't know its name and location

can you help me with that please.

goetz

The best way would be to copy the lib into the frameworks folder inside the app and use install_name_tool to change the path. Have a look at the "Mac Deployment":http://developer.qt.nokia.com/doc/qt-4.7/deployment-mac.html page of the Qt docs on some information how to do this.

abdol

Thank you Volker :),
I solved the problem. You were right, I used ln to put a link of libmysqlclient.18.dylib in mac's lib folder.
Also the link you just put is awesome. Thanks a lot.

goetz

If you want to ship that application to someone else, you'd better put the libs into the application bundle (if allowed by the license, of course).

abdol

I appreciate your helps and consider this. Thank you so much :)