MongoDB integration with Qt

[enne9]

Hello,
in my current project, I'm trying to move from MySQL to MongoDB.
Any idea about where to start? I didn't find anything really clear and recent, maybe someone can point me in the right direction.

In particular, I'm searching for some basic examples of usage and especially how to deal with driver installation.
Thanks

[Christian Ehrlicher]

Qt has no driver for MongoDB, you have to use the MongoDB api directly or write a Qt driver for it, see for example here: https://forum.qt.io/topic/37645/how-to-connect-mongodb-with-qt/4 (the search function is your friend)

[enne9]

I already saw it but all github links are broken.

[Christian Ehrlicher]

As I already said you've three possibilities

• don't use MongoDB
• write a proper Qt plugin
• use the MongoDB api directly.

[SGaist]

Hi,

Did you check the official MongoDB C API ?

[enne9]

I did as you suggested to me and I'm including the mongocxx library.
Unfortunatelly I get a
usr/local/include/bsoncxx/v_noabi/bsoncxx/types.hp:39: Parse error at "{"
and I don't know what to do, since a collage of mine working on the same project is not getting this problem (using the exact same code).

The error is in correspondence of

enum class type : std::uint8_t {
#define BSONCXX_ENUM(name, val) k_##name = val,
#include <bsoncxx/enums/type.hpp>
#undef BSONCXX_ENUM
};

If I remove type : std::uint8_t it then complains about other errors...
Any suggestions?

[SGaist]

Hi,

Can you show the code that you are using that triggers that error ?

[enne9]

Sorry, but it is confidential and I'm not sure I can share it.
Using #ifndef Q_MOC_RUN as suggested here https://bugreports.qt.io/browse/QTBUG-80578 makes the compilation error disappears but the program then crashes immediately at runtime.

[SGaist]

In that kind of case, you can also provide a minimal example that shows the issue.

And what does the stack trace of the crash say ?

[enne9]

home/../mongo/bsoncxx/v_noabi/bsoncxx/types.hp:39: Parse error at "{"
make[1]: *** [Makefile:1117: moc_server.cpp] Error 1

This is what I get in the compilation output, if it is useful

[SGaist]

Well, without the code, it doesn't help much.

[enne9]

A minimal piece of code to reproduce the error is already available here https://bugreports.qt.io/browse/QTBUG-80578, but it seems to be a bug. Unfortunately, I didn't find any workaround and I'm unable to continue with the project.

[SGaist]

You wrote that the compilation was successful so that part is fine, isn't it ?

As for the run time crash, what is the stack trace ?

[enne9]

[SGaist]

Do you have the same issue if you write a minimal test application using only bsoncxx ?

[enne9]

In the end, it was a problem of compatibility between mongocxx and my Qt version. Installing a previous release fixed the issue.

[Ahmed000001]

@enne9 said in MongoDB integration with Qt:

n mongocxx and my Qt version. I

so, what was the compatible versions?