QPSQL driver not loaded even though QPSQL driver is available

adityar

I am using Qt 4.8.2 to build a desktop app on linux that connects to a PostgreSQL database running in the background. I have build and installed the QPSQL driver. When I try to establish a connection to the database , I get the "Driver Not Loaded, Driver Not Loaded " error , even though QSqlDatabase reports that "QPSQL" is available. Here is my code :

@ QSqlDatabase db = QSqlDatabase::addDatabase("QPSQL");
db.setHostName("localhost");
db.setDatabaseName("demo");
db.setUserName("root");
db.setPassword("ET_DIAGDB_CONTROL");
db.setPort(5432);

@

on running the code , I get the following error:

QSqlDatabase: QPSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL3 QMYSQL QODBC3 QODBC QPSQL7 QPSQL

I have checked that libqslqpsql.so is present in my plugins/sqldrivers directory and i have included the path to that directory in my paths

MementoMori

in the executable's path make sure you have the following files (I suppose you're using windows):

comerr32.dll
gssapi32.dll
k5sprt32.dll
krb5_32.dll
libgcc_s_dw2-1.dll
libiconv-2.dll
libintl-8.dll
libpq.dll
mingwm10.dll
msvcr71.dll

you may also need:

libssl32.dll
libeay32.dll
ssleay32.dll

HTH

adityar

I am on linux

issam

libpq.so.5 is (yum install PostgreSQL-libs) necessary for g++ to link the executable (Remember that in a Linux environment shared libraries have the extension .so not .dll).

In the other hand, may be, there are some lines that you must add to your pro file (qMakefile):

The variables accessible with this operator are typically used to enable third party plugins and components to be integrated with Qt. For example, a Qt Designer plugin can be installed alongside Qt Designer's built-in plugins if the following declaration is made in its project file:

@
target.path = $$[QT_INSTALL_PLUGINS]/designer
INSTALLS += target
@

See in the documentation: qmake Advanced Usage

good luck :)

MementoMori

in linux you should use ldd to find the dependencies of an executable/shared object

for example:

@
$ ldd libqsqlpsql.so
linux-gate.so.1 => (0xb77c4000)
libpq.so.5 => /usr/lib/libpq.so.5 (0xb7770000)
libQtSql.so.4 => /home/filippo/QtSDK/Desktop/Qt/4.8.1/gcc/lib/libQtSql.so.4 (0xb7730000)
libQtCore.so.4 => /home/filippo/QtSDK/Desktop/Qt/4.8.1/gcc/lib/libQtCore.so.4 (0xb7448000)
libstdc++.so.6 => /usr/lib/i386-linux-gnu/libstdc++.so.6 (0xb7363000)
libgcc_s.so.1 => /lib/i386-linux-gnu/libgcc_s.so.1 (0xb7345000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xb71a0000)
...

@

man ldd for further details.

adityar

Thanks! Idd told me that libpq.so.5 was missing. I included it in my LD_LIBRARY_PATH and it works now .

issam

good