Building QT with "windeployqt": not connect to database (ODBC)

AndreaCT

Hello, and sorry for my not perfect English.

I developed a simple UI application with QT, connected to a local database (using XAMPP). I downloaded the ODBC connector (https://dev.mysql.com/downloads/connector/odbc) and configured the connection to the database through ODBC Data Sources. In the main I connect to the database and everything works correctly.

Then I generated the executable of my project and related dependencies using the windeployqt command from terminal. I put all in the same folder and the executable works perfectly.

Then I moved everything (exe + dependencies) to another PC (with the same database locally and xampp running), but here the connection to the database fails.

How can I solve it? Thanks!

SGaist

Hi and welcome to devnet,

Did you check that you also deployed the connector's dll and its dependencies along with your application ?

AndreaCT

That's all! Into sqldrivers there is qsqlodbc.dll

SGaist

Use a tool like Dependency Walker to find the direct dependencies you need to deploy.

AndreaCT

Mmh this is the output:

How can recognize and integrate the direct dependencies?

SGaist

This is for your application executable, you should check the database plugin.

AndreaCT

Mmh so I don't have to open my exe in dependency walker?
Sorry and thank you for your patience...

AndreaCT

C:\Qt\5.14.2\mingw73_32\plugins\sqldrivers\qsqlodbc.dll
I have to run dependency walker on it, right?

AndreaCT

Eventually, this is the output:

These are already present:

LIBGCC_S_DW2-1.DLL
LIBSTDC++-6.DLL
QT5CORE.DLL
QT5SQL.DLL

I downloaded the other 3 [https://www.dll-files.com/search.dll.html], and added these in the same folder.

SGaist

And the ODBC dll ?

AndreaCT

ODBC32.dll, no?

SGaist

Yes, did you check the dependencies of that one ?

AndreaCT

Download and put inside all the missing dll?

AndreaCT

Unfortunately the problem persists

hskoglund

Hi, just guessing, are you using 127.0.0.1 (or localhost) to connect to the database also on the new PC? Also, have you checked that you can reach the database with MySQL workbench?

AndreaCT

Yes to both

hskoglund

Ok. Is it same version of Windows 10 on both computers?

JSher

Is the ODCB connection created on 2nd computer? Also with mysql connector you need Visual C++2015 distro.

--James

AndreaCT

@hskoglund Yes

AndreaCT

@JSher No, I just tried to print the error on a label with db.lastError() and the output is: "[Microsoft][Driver Manager ODBC] Nome origine dati non trovato e driver predefinito non specificato. QODBC3: Unable to connect"