PostgreSQL and Windows Community Version

[jacek]

This was for, I believe, LIBPQ.DLL, I do not get this error when I try the other plugins.

It looks like it can't find the PostgreSQL client library. Find that file and copy it to the same directory where your executable is (you might need other DLLs too, so check it with Dependency Walker).

[graeme]

Just done that and whilst Dependency Walker is now happy, my app refuses to play ball

I have now put the driver along with the dlls in the plugin directory and in an sqldrivers directory in the same direcotiry as the executable but no joy.

[jacek]

I have now put the driver along with the dlls in the plugin directory and in an sqldrivers directory in the same direcotiry as the executable but no joy.

Are you 100% sure that both the plugin and the application were built in the same mode (i.e. both in debug mode or both in release mode)?

[graeme]

I have both versions of the plugin qsqlpsql.dll & qsqlpsqld.dll.
I tried with a release version of my app, followed by a debug version. I currently have a debug version.
The postgresql dll are (I believe) release versions (no *d.dll)

Should I just revert to the release version of the app?

[jacek]

Should I just revert to the release version of the app?

No, since you have both versions of the plugin.

What does exactly QSqlDatabase::drivers() return when you invoke it from your application? What parameters do you pass to QSqlDatabase::addDatabase()?

[graeme]

drivers returns:

QSQLITE
QODBC3
QODBC

The code you requested is:

// Get the connection, if it exists
QSqlDatabase dbConn = QSqlDatabase::database(connName,false);
// Check that the driver is available
if (!QSqlDatabase::isDriverAvailable(connType))
	throw sqlE(dbConn, QObject::tr("The Database driver ")+ connType + QObject::tr("is not available"));

// Get the connection, if it exists
QSqlDatabase dbConn = QSqlDatabase::database(connName,false);
// Check that the driver is available
if (!QSqlDatabase::isDriverAvailable(connType))
	throw sqlE(dbConn, QObject::tr("The Database driver ")+ connType + QObject::tr("is not available"));

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followed by:

// Okay the connection doesn't exist so let's add it using the appropriate driver type
dbConn = QSqlDatabase::addDatabase(connType,connName);

// Okay the connection doesn't exist so let's add it using the appropriate driver type
dbConn = QSqlDatabase::addDatabase(connType,connName);

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The result is "... The Database driver QPSQLis not available"

[jacek]

This is weird. I've never had any problems with QPSQL driver on windows.

qmake -o Makefile "INCLUDEPATH+=C:\psql\include" "LIBS+=C:\psql\lib\ms\libpq.lib" psql.pro
...
This generated .a and .dll files in the C:\Qt\4.1.1\plugins\sqldrivers directory.

What compiler do you use? I guess you use MinGW, if you got an .a file, but then you shouldn't be able to use the libpq.lib file.

Try:

qmake -o Makefile "INCLUDEPATH+=C:\psql\include" "LIBS+=C:\psql\lib" psql.pro

[graeme]

I'm using Mingw32

The switch you suggest gives an error:

C:\psql\lib: No such file

following you line of thought (I believe) I tried

qmake -o Makefile "INCLUDEPATH+=C:\psql\include" "LIBS+=C:\psql\lib\libpq.a" psql.pro

that created the files but still nothing when I run the program

[jacek]

following you line of thought (I believe) I tried
qmake -o Makefile "INCLUDEPATH+=C:\psql\include" "LIBS+=C:\psql\lib\libpq.a" psql.pro

Yes, or "LIBS+= -LC:\psql\lib\ -lpq".

that created the files but still nothing when I run the program

I hope you have removed all copies of the old driver.

I always configure Qt like this:

configure -L C:\...\psql\lib -I C:\...\psql\include -plugin-sql-psql ...

Which Qt version do you use exactly? In one of the older versions one had to remove some keys from the registry in case of problems with plugins. It was something around HKEY_CURRENT_USER\Software\Trolltech\OrganizationD efaults\Qt Plugin Cache...

[graeme]

I'm using 4.1.1

I removed the old drivers, in fact I renamed the old file ran my program - no drivers. Copied the qsqlited.dll into the sqldrivers folder of my app it found that driver. Removed it - no drivers.

Then ran the make. It created a new sqldrivers directory with the new psql driver. I copied it into my program sqldrivers directory and deleted it from the qt directory. But alas...

I'll look for the registry entry.

[graeme]

The registry only has the default value

[jacek]

I'm using 4.1.1
...
I'll look for the registry entry.

If there was a problem with loading the driver Qt marked such plugin as invalid in the registry and then just ignored it (even after the problem was fixed), but AFAIR this was Qt 4.0.0 or 4.0.1.

[graeme]

Okay I'm running out of ideas.

From all of this I believe that the problem lies with how the dll is being created. So would getting an MS compiler help? I guess that I could download their C++ compiler and try it out. Or would it be better to configue and rebuild Qt?