Postgresql driver is not found

[alxdef]

@SGaist

I think that library is not in business.

[SGaist]

I meant that you should run Dependency Walker on the OpenSSL dlls and that it would have likely been the VC runtime missing.

[alxdef]

@SGaist

It looks like infinite loop…

[SGaist]

Did you copy the VC runtime in the same folder as the OpenSSL library ?

[Christian Ehrlicher]

@alxdef Your first screenshot tells you that libstdc++-6.dll is missing.

[SGaist]

@Christian-Ehrlicher said in Postgresql driver is not found:

@alxdef Your first screenshot tells you that libstdc++-6.dll is missing.

Arf ! I missed that one. Good catch :-)

[alxdef]

@Christian-Ehrlicher

These libs are present in my app executable folder:

sqldrivers\qsqlpsql.dll
platforms\qwindows.dll
vcruntime140.dll
Qt5Sql.dll
Qt5Core.dll
msvcrt.dll
libstdc++-6.dll
libssl-1_1-x64.dll
libpq.dll
libintl-8.dll
libcrypto-1_1-x64.dll

[alxdef]

So there are no ideas…

[Bonnie]

Did you get libpq from the official site? I've just had a try.
I think it is probably due to the file you were all ignoring: libintl-8.dll --> it depends on libiconv-2.dll, which you didn't copy.
When you use Dependency Walker on libpq.dll, check all the yellow icons, not only in the upper part tree, but also in the lower part list (those are all the dlls recursively)...
But there may also be some many "false alarms", especially those dlls needed by system dlls / vc runtimes (e.g.: api-ms-...), you'll need to distinguish them by yourself.
I mainly check those start with "lib" (MinGW style) and "q" (Qt libs).
Or you can manually expand all the tree items recursively, just skip when it is a system / vc runtime.

[alxdef]

@Bonnie
Thanks for advice. Now application debug output looks like this:

Got keys from plugin meta data ("QPSQL7", "QPSQL")
loaded library "…/debug/sqldrivers/qsqlpsql.dll"
QFactoryLoader::QFactoryLoader() checking directory path "…/debug/accessible" ...
QFactoryLoader::QFactoryLoader() checking directory path "…/debug/accessiblebridge" ...
QLibraryPrivate::unload succeeded on "…/debug/sqldrivers/qsqlpsql.dll" 
QLibraryPrivate::unload succeeded on "…/debug/platforms/qwindows.dll" 
21:31:17: *.exe exited with code 0

But I still catch "Driver not loaded" using this code:

if (!this->app_conn.isValid())
{
  //…
}

if (!this->app_conn.open())
{
  //…
}

[SGaist]

Can you show the code your are actually using to setup the database ?

The output you show does not present any error quite the contrary.

[alxdef]

@SGaist

this->app_conn = QSqlDatabase();

  this->app_conn.addDatabase(this->db_type);
  this->app_conn.setDatabaseName(this->db_name);
  this->app_conn.setHostName(this->db_host);
  this->app_conn.setPort(this->db_port);
  this->app_conn.setUserName(this->user_name);
  this->app_conn.setPassword(this->user_password);

this->db_type is "QPSQL".

[SGaist]

You are using QSqlDatabase in the wrong manner.

addDatabase is a static member, you are manipulating an invalid object.

As the QSqlDatabase warns about: do not store local variables of that type. The class already provides everything needed to handle the objects you create from it.

[alxdef]

@SGaist said in Postgresql driver is not found:

QSqlDatabase

Many thanks! Connected Ok.

[alxdef]

So is it necessary to grab all "Debug" DLLs and place them to "Release"? How to avoid this crutch?

[SGaist]

What debug dll ?

[alxdef]

@SGaist

\sqldrivers\qsqlpsql.dll
\platforms\qwindows.dll
\vcruntime140.dll
\Qt5Sql.dll
\Qt5Core.dll
\msvcrt.dll
\libstdc++-6.dll
\libssl-1_1-x64.dll
\libpq.dll
\libintl-8.dll
\libiconv-2.dll
\libcrypto-1_1-x64.dll

[SGaist]

Ah, you meant the content of the Debug folder.

One thing you can do is go in the Run part of the Project panel and modify the PATH environment variable to include the path to these dlls.

[alxdef]

@SGaist
I've made additional folder inside my project and move all DLLs into it. After that add path to this folder in PATH variable. It works but this method is crutch anyway…

[SGaist]

On Windows there's two way to find .dlls:

• they are in the same folder
• they are in a folder in your PATH environment variable

Qt Creator does the change for Qt for you based on which kit you are using. Since you use external dependencies, it's up to you to provide a mean to find your dependencies dlls. And no, modifying your system's PATH environment is not the correct way.