Location of Qt 5.4 source code

[slesher]

yeah... Thanks a lot!
It was realy there...
Maybe it was just my fault but I think you should correct this path in the documentation.

[slesher]

One more question about the driver...
I did as in in the instructions:
@set INCLUDE=%INCLUDE%;D:\OClient\product\11.2.0\cl
ient_1\oci\include
set LIB=%LIB%;D:\OClient\product\11.2.0\cl
ient_1\oci\lib\msvc
cd %QTDIR%\5.4\Src\qtbase\src\plugins\sqldrivers\oci
qmake oci.pro
mingw32-make@

so, as i understood, it has built me a driver, but i don't understand where it is now. the set PATH=%PATH%;D:\OClient\product\11.2.0\client_1\bin is set in my environmental variables. but calling the qDebug()<<QSqlDatabase::drivers(); doesn't print QOCI in the list of drivers.

now i have the next files in my 5.4\Src\qtbase\src\plugins\sqldrivers\oci directory:
@-|.moc
---|debug
------|main.moc
------|moc_qsql_oci_p.cpp
---|release
------|main.moc
------|moc_qsql_oci_p.cpp
-|.obj
---|debug
------|main.o
------|moc_qsql_oci_p.o
------|qsql_oci.o
------|qsqlocid_resource_res.o
---|release
------|main.o
------|moc_qsql_oci_p.o
------|qsql_oci.o
------|qsqloci_resource_res.o
-|.pch
---|debug
---|release
-|main.cpp
-|Makefile
-|Makefile.Debug
-|Makefile.Release
-|oci.json
-|oci.pro
-|qsqloci_resource.rc
-|qsqlocid_resource.rc
-|README@

[slesher]

Here is the list of operations from the comand prompt from the start of the reply to the end (it seems to me that everything went ok):
First part(because here is a limit to 6000 characters):
@
mingw32-make -f Makefile.Release all
mingw32-make[1]: Entering directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sq
ldrivers/oci'
D:\apps\QT5_4\5.4\mingw491_32\bin\moc.exe -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_N
O_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT
CORE_LIB -D__GNUC_ -DWIN32 -ID:/apps/QT5_4/5.4/Src/qtbase/mkspecs/win32-g++ -I
D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sqldrivers/oci -ID:/apps/QT5_4/5.4/ming
w491_32/include/QtCore/5.4.0 -ID:/apps/QT5_4/5.4/mingw491_32/include/QtCore/5.4.
0/QtCore -ID:/apps/QT5_4/5.4/mingw491_32/include/QtSql/5.4.0 -ID:/apps/QT5_4/5.4
/mingw491_32/include/QtSql/5.4.0/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/include -
ID:/apps/QT5_4/5.4/mingw491_32/include/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/inc
lude/QtCore main.cpp -o .moc\release\main.moc
g++ -c -pipe -fno-keep-inline-dllexport -O2 -std=c++0x -fno-exceptions -frtti -W
all -Wextra -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCE
PTIONS -DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I"D:\apps\QT5_4
\5.4\mingw491_32\include\QtCore\5.4.0" -I"D:\apps\QT5_4\5.4\mingw491_32\include
QtCore\5.4.0\QtCore" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0" -I"D:
\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0\QtSql" -I"D:\apps\QT5_4\5.4\ming
w491_32\include" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql" -I"D:\apps\QT5_
4\5.4\mingw491_32\include\QtCore" -I".moc\release" -I"%INCLUDE%" -I"D:\OClient\p
roduct\11.2.0\client_1\oci\include" -I"........\mkspecs\win32-g++" -o .obj\re
lease\main.o main.cpp
g++ -c -pipe -fno-keep-inline-dllexport -O2 -std=c++0x -fno-exceptions -frtti -W
all -Wextra -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCE
PTIONS -DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I"D:\apps\QT5_4
\5.4\mingw491_32\include\QtCore\5.4.0" -I"D:\apps\QT5_4\5.4\mingw491_32\include
QtCore\5.4.0\QtCore" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0" -I"D:
\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0\QtSql" -I"D:\apps\QT5_4\5.4\ming
w491_32\include" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql" -I"D:\apps\QT5_
4\5.4\mingw491_32\include\QtCore" -I".moc\release" -I"%INCLUDE%" -I"D:\OClient\p
roduct\11.2.0\client_1\oci\include" -I"........\mkspecs\win32-g++" -o .obj\re
lease\qsql_oci.o ......\sql\drivers\oci\qsql_oci.cpp
D:\apps\QT5_4\5.4\mingw491_32\bin\moc.exe -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_N
O_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT
CORE_LIB -D__GNUC_ -DWIN32 -ID:/apps/QT5_4/5.4/Src/qtbase/mkspecs/win32-g++ -I
D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sqldrivers/oci -ID:/apps/QT5_4/5.4/ming
w491_32/include/QtCore/5.4.0 -ID:/apps/QT5_4/5.4/mingw491_32/include/QtCore/5.4.
0/QtCore -ID:/apps/QT5_4/5.4/mingw491_32/include/QtSql/5.4.0 -ID:/apps/QT5_4/5.4
/mingw491_32/include/QtSql/5.4.0/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/include -
ID:/apps/QT5_4/5.4/mingw491_32/include/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/inc
lude/QtCore ......\sql\drivers\oci\qsql_oci_p.h -o .moc\release\moc_qsql_oci_p
.cpp
g++ -c -pipe -fno-keep-inline-dllexport -O2 -std=c++0x -fno-exceptions -frtti -W
all -Wextra -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCE
PTIONS -DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I"D:\apps\QT5_4
\5.4\mingw491_32\include\QtCore\5.4.0" -I"D:\apps\QT5_4\5.4\mingw491_32\include
QtCore\5.4.0\QtCore" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0" -I"D:
\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0\QtSql" -I"D:\apps\QT5_4\5.4\ming
w491_32\include" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql" -I"D:\apps\QT5_
4\5.4\mingw491_32\include\QtCore" -I".moc\release" -I"%INCLUDE%" -I"D:\OClient\p
roduct\11.2.0\client_1\oci\include" -I"........\mkspecs\win32-g++" -o .obj\re
lease\moc_qsql_oci_p.o .moc\release\moc_qsql_oci_p.cpp
windres -i qsqloci_resource.rc -o .obj\release\qsqloci_resource_res.o --include-
dir=. -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS
-DQT_NO_DEBUG -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB
g++ -Wl,-s -shared -Wl,-subsystem,windows -Wl,--out-implib,D:\apps\QT5_4\5.4\Src
\qtbase\plugins\sqldrivers\libqsqloci.a -o ........\plugins\sqldrivers\qsqloc
i.dll .obj/release/main.o .obj/release/qsql_oci.o .obj/release/moc_qsql_oci_p.o
-L%LIB% -LD:\OClient\product\11.2.0\client_1\oci\lib\msvc -loci -LD:/apps/QT5_4
/5.4/mingw491_32/lib -lQt5Sql -lQt5Core .obj\release\qsqloci_resource_res.o
mingw32-make[1]: Leaving directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sql
drivers/oci'
mingw32-make -f Makefile.Debug all
mingw32-make[1]: Entering directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sq
ldrivers/oci'
D:\apps\QT5_4\5.4\mingw491_32\bin\moc.exe -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_N
O_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -D__
GNUC__ -DWIN32 -ID:/apps/QT5_4/5.4/Src/qtbase/mkspecs/win32-g++ -ID:/apps/QT5_4/
5.4/Src/qtbase/src/plugins/sqldrivers/oci -ID:/apps/QT5_4/5.4/mingw491_32/includ
e/QtCore/5.4.0 -ID:/apps/QT5_4/5.4/mingw491_32/include/QtCore/5.4.0/QtCore -ID:/
apps/QT5_4/5.4/mingw491_32/include/QtSql/5.4.0 -ID:/apps/QT5_4/5.4/mingw491_32/i
nclude/QtSql/5.4.0/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/include -ID:/apps/QT5_4
/5.4/mingw491_32/include/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/include/QtCore ma
in.cpp -o .moc\debug\main.moc
@

[slesher]

second part
@g++ -c -pipe -fno-keep-inline-dllexport -g -std=c++0x -fno-exceptions -frtti -Wa
ll -Wextra -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCEP
TIONS -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I"D:\apps\QT5_4\5.4\mingw491_3
2\include\QtCore\5.4.0" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtCore\5.4.0\Qt
Core" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0" -I"D:\apps\QT5_4\5.4
\mingw491_32\include\QtSql\5.4.0\QtSql" -I"D:\apps\QT5_4\5.4\mingw491_32\include
" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql" -I"D:\apps\QT5_4\5.4\mingw491_
32\include\QtCore" -I".moc\debug" -I"%INCLUDE%" -I"D:\OClient\product\11.2.0\cli
ent_1\oci\include" -I"........\mkspecs\win32-g++" -o .obj\debug\main.o main.c
pp
g++ -c -pipe -fno-keep-inline-dllexport -g -std=c++0x -fno-exceptions -frtti -Wa
ll -Wextra -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCEP
TIONS -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I"D:\apps\QT5_4\5.4\mingw491_3
2\include\QtCore\5.4.0" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtCore\5.4.0\Qt
Core" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0" -I"D:\apps\QT5_4\5.4
\mingw491_32\include\QtSql\5.4.0\QtSql" -I"D:\apps\QT5_4\5.4\mingw491_32\include
" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql" -I"D:\apps\QT5_4\5.4\mingw491_
32\include\QtCore" -I".moc\debug" -I"%INCLUDE%" -I"D:\OClient\product\11.2.0\cli
ent_1\oci\include" -I"........\mkspecs\win32-g++" -o .obj\debug\qsql_oci.o ..
....\sql\drivers\oci\qsql_oci.cpp
D:\apps\QT5_4\5.4\mingw491_32\bin\moc.exe -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_N
O_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -D__
GNUC__ -DWIN32 -ID:/apps/QT5_4/5.4/Src/qtbase/mkspecs/win32-g++ -ID:/apps/QT5_4/
5.4/Src/qtbase/src/plugins/sqldrivers/oci -ID:/apps/QT5_4/5.4/mingw491_32/includ
e/QtCore/5.4.0 -ID:/apps/QT5_4/5.4/mingw491_32/include/QtCore/5.4.0/QtCore -ID:/
apps/QT5_4/5.4/mingw491_32/include/QtSql/5.4.0 -ID:/apps/QT5_4/5.4/mingw491_32/i
nclude/QtSql/5.4.0/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/include -ID:/apps/QT5_4
/5.4/mingw491_32/include/QtSql -ID:/apps/QT5_4/5.4/mingw491_32/include/QtCore ..
....\sql\drivers\oci\qsql_oci_p.h -o .moc\debug\moc_qsql_oci_p.cpp
g++ -c -pipe -fno-keep-inline-dllexport -g -std=c++0x -fno-exceptions -frtti -Wa
ll -Wextra -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCEP
TIONS -DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB -I. -I"D:\apps\QT5_4\5.4\mingw491_3
2\include\QtCore\5.4.0" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtCore\5.4.0\Qt
Core" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql\5.4.0" -I"D:\apps\QT5_4\5.4
\mingw491_32\include\QtSql\5.4.0\QtSql" -I"D:\apps\QT5_4\5.4\mingw491_32\include
" -I"D:\apps\QT5_4\5.4\mingw491_32\include\QtSql" -I"D:\apps\QT5_4\5.4\mingw491_
32\include\QtCore" -I".moc\debug" -I"%INCLUDE%" -I"D:\OClient\product\11.2.0\cli
ent_1\oci\include" -I"........\mkspecs\win32-g++" -o .obj\debug\moc_qsql_oci_
p.o .moc\debug\moc_qsql_oci_p.cpp
windres -i qsqlocid_resource.rc -o .obj\debug\qsqlocid_resource_res.o --include-
dir=. -DUNICODE -DQT_NO_CAST_TO_ASCII -DQT_NO_CAST_FROM_ASCII -DQT_NO_EXCEPTIONS
-DQT_PLUGIN -DQT_SQL_LIB -DQT_CORE_LIB
g++ -shared -Wl,-subsystem,windows -Wl,--out-implib,D:\apps\QT5_4\5.4\Src\qtbase
\plugins\sqldrivers\libqsqlocid.a -o ........\plugins\sqldrivers\qsqlocid.dll
.obj/debug/main.o .obj/debug/qsql_oci.o .obj/debug/moc_qsql_oci_p.o -L%LIB% -L
D:\OClient\product\11.2.0\client_1\oci\lib\msvc -loci -LD:/apps/QT5_4/5.4/mingw4
91_32/lib -lQt5Sqld -lQt5Cored .obj\debug\qsqlocid_resource_res.o
mingw32-make[1]: Leaving directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sql
drivers/oci'

D:\apps\QT5_4\5.4\Src\qtbase\src\plugins\sqldrivers\oci>@

[JKSH]

After nmake, I believe you need nmake install

[SGaist]

The documentation has been updated for the next release

[slesher]

Thanks for updating the documentation

Okay, i did mingw32-make install
So it copied qsqloci.dll and qsqlocid.dll to the sqldrivers and Qt5Sql_QOCIDriverPlugin.cmake (and i don't know what it is)
For being sure, i copied these .dll and libqsqlocid.a, libqsqloci.a to every folder which i thought could need them. When making a new project, qDebug()<<QSqlDatabase::drivers(); prints:
@("QSQLITE", "QMYSQL", "QMYSQL3", "QOCI", "QOCI8", "QODBC", "QODBC3", "QPSQL", "QPSQL7")@

But after i had tried to connect to my database, it failed and lastError().text() returned the next: "Driver not loaded Driver not loaded"

My code of connection:
@qDebug()<<QSqlDatabase::drivers();
QSqlDatabase db;
db.addDatabase("QOCI");
db.setHostName("192.168.2.");
db.setDatabaseName("orcl.slesherdb.");
db.setUserName("");
db.setPassword("");
bool ok = db.open();
qDebug()<<db.lastError().text();@

My listing of cmd after mingw32-make install

@D:\apps\QT5_4\5.4\Src\qtbase\src\plugins\sqldrivers\oci>mingw32-make install
mingw32-make -f Makefile.Release install
mingw32-make[1]: Entering directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sq
ldrivers/oci'
copy /y "........\plugins\sqldrivers\qsqloci.dll" "D:\apps\QT5_4\5.4\mingw491
_32\plugins\sqldrivers\qsqloci.dll"
1 file(s) copied.
copy /y D:\apps\QT5_4\5.4\Src\qtbase\lib\cmake\Qt5Sql\Qt5Sql_QOCIDriverPlugin.cm
ake D:\apps\QT5_4\5.4\mingw491_32\lib\cmake\Qt5Sql
1 file(s) copied.
mingw32-make[1]: Leaving directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sql
drivers/oci'
mingw32-make -f Makefile.Debug install
mingw32-make[1]: Entering directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sq
ldrivers/oci'
copy /y "........\plugins\sqldrivers\qsqlocid.dll" "D:\apps\QT5_4\5.4\mingw49
1_32\plugins\sqldrivers\qsqlocid.dll"
1 file(s) copied.
copy /y D:\apps\QT5_4\5.4\Src\qtbase\lib\cmake\Qt5Sql\Qt5Sql_QOCIDriverPlugin.cm
ake D:\apps\QT5_4\5.4\mingw491_32\lib\cmake\Qt5Sql
1 file(s) copied.
mingw32-make[1]: Leaving directory 'D:/apps/QT5_4/5.4/Src/qtbase/src/plugins/sql
drivers/oci'@

[SGaist]

I'd say the obi dll(s) can't be found by your application. Go to the run part of the Project panel and update the PATH environment variable by adding "D:\OClient\product\11.2.0\client_1\oci\lib\msvc" if it contains the dlls or the corresponding folder in there

[slesher]

Unfortunately, it has already been added.
And it has also been added Windows folder, System32 folder, and the bin folders of Oracle client and Oracle server, where oci.dll is placed

[slesher]

I did as you wrote here:http://qt-project.org/forums/viewthread/21546
So I added new environmental variable QT_DEBUG_PLUGINS = 1
There are lots of things I can't understand
So here is listing of application output:

@QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqloci.a"
"Plugin verification data mismatch in 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqloci.a'"
not a plugin
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqlocid.a"
"Plugin verification data mismatch in 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqlocid.a'"
not a plugin
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/oci.dll"
"Plugin verification data mismatch in 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/oci.dll'"
not a plugin
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/qsqloci.dll"
Found metadata in lib D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/qsqloci.dll, metadata=
{
"IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
"MetaData": {
"Keys": [
"QOCI8",
"QOCI"
]
},
"className": "QOCIDriverPlugin",
"debug": false,
"version": 328704
}

"The plugin 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/qsqloci.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
not a plugin
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/qsqlocid.dll"
Found metadata in lib D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/qsqlocid.dll, metadata=
{
"IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
"MetaData": {
"Keys": [
"QOCI8",
"QOCI"
]
},
"className": "QOCIDriverPlugin",
"debug": true,
"version": 328704
}

Got keys from plugin meta data ("QOCI8", "QOCI")

Got keys from plugin meta data ("windows")
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/Tools/QtCreator/bin/build-sql-Desktop_Qt_5_4_0_MinGW_32bit-Debug/debug/platforms" ...
loaded library "D:/apps/QT5_4/5.4/mingw491_32/plugins/platforms/qwindowsd.dll"
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/5.4/mingw491_32/plugins/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/Tools/QtCreator/bin/build-sql-Desktop_Qt_5_4_0_MinGW_32bit-Debug/debug/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/5.4/mingw491_32/plugins/platforminputcontexts" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/Tools/QtCreator/bin/build-sql-Desktop_Qt_5_4_0_MinGW_32bit-Debug/debug/platforminputcontexts" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/5.4/mingw491_32/plugins/generic" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/Tools/QtCreator/bin/build-sql-Desktop_Qt_5_4_0_MinGW_32bit-Debug/debug/generic" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/5.4/mingw491_32/plugins/styles" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/Tools/QtCreator/bin/build-sql-Desktop_Qt_5_4_0_MinGW_32bit-Debug/debug/styles" ...
QFactoryLoader::QFactoryLoader() checking directory path "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqloci.a"
"Plugin verification data mismatch in 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqloci.a'"
not a plugin
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqlocid.a"
"Plugin verification data mismatch in 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/libqsqlocid.a'"
not a plugin
QFactoryLoader::QFactoryLoader() looking at "D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/oci.dll"
"Plugin verification data mismatch in 'D:/apps/QT5_4/5.4/mingw491_32/plugins/sqldrivers/oci.dll'"
not a plugin

@

[SGaist]

Did you check the environment variable value in the run part ? Depending on when you did your modification, it might be not up to date

[slesher]

[quote author="SGaist" date="1424219154"]Did you check the environment variable value in the run part ? Depending on when you did your modification, it might be not up to date[/quote]

I'm not sure if I understood you. I changed only PATH variable, the other ones are by default.
And I am confused why QT_DEBUG_PLUGINS tells me that some of .dlls are not plugins, or uses incompatible Qt library. (Cannot mix debug and release libraries.)

[SGaist]

Some people change their system PATH rather than just in Qt Creator, that's why I asked the double check of PATH.

IIRC both debug and release dlls are stored in the same folder so Qt will check them all hence the incompatibility error message.

[slesher]

The problem is solved.
I have changed the part of code of connection:
@QSqlDatabase db;
db.addDatabase("QOCI");@

instead of

@QSqlDatabase db = QSqlDatabase::addDatabase("QOCI");@

When I guessed to change back, everything was ok.

Thanks a lot to all!