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I use PostgreSQL 9.6.17 (installed on linux server on LAN) and have
Win10 (or Win7) clients with installed Python 3.7 or 3.8 and PyQt
5.13.2, and my PyQt5 app that uses that PostgreSQL server works ok,
but I really don't know what I'm doing.<br>
<br>
I'll describe the problem. If I don't have PostgreSQL installed on
Win client (I don't need it because I use PostgreSQL on linux
server) or have installed it but not in path, my app crashes with
the error: "QSqlDatabase: QPSQL driver not loaded".<br>
<br>
So, I need some drivers. And I install PostgreSQL 9.6.x on Win
client and have it in path and after that everything works ok, but
only if I had luck and picked the right x in PostgreSQL 9.6.x
version.<br>
<br>
The alternative is that I don't install PostgreSQL 9.6.x (why would
I need to install it) on client machine and just copy some dll files
at the app directory. If I find the right files (drivers),
everything works ok, but if I don't, the app crashes with the error:
"QSqlDatabase: QPSQL driver not loaded" or worse, recognize the
PostgreSQL database on server, works ok some time, but after the
first, second or third query it crashes.<br>
<br>
Some driver combinations I copy to my app directory that work with
PyQt 5.13.2:<br>
<br>
1.<br>
Timestamp Size File<br>
25/02/2016 07:19 1,015,973 libiconv-2.dll<br>
07/01/2016 09:02 1,550,023 libintl-8.dll<br>
10/07/2019 20:20 145,408 libpq.dll<br>
<br>
2.<br>
Timestamp Size File<br>
21/06/2019 14:43 1,218,048 libeay32.dll<br>
25/02/2016 07:19 1,015,973 libiconv-2.dll<br>
07/01/2016 09:02 1,550,023 libintl-8.dll<br>
10/07/2019 20:20 145,408 libpq.dll<br>
21/06/2019 14:43 276,992 ssleay32.dll<br>
<br>
If I install PyQt 5.14 or 5.15 (instead of PyQt 5.13.2), the app
crashes, and I am afraid to upgrade PyQt5.<br>
<br>
So, my question is:<br>
How do I know which drivers I should copy to my app directory with
various version of PyQt5, that's the mistery to me. And also if
copying the drivers to my app directory is the right way at all?<br>
<br>
There's a fine answer here:<br>
<br>
<a class="moz-txt-link-freetext" href="https://stackoverflow.com/questions/20884010/qt5-failed-to-load-psql-driver-in-windows">https://stackoverflow.com/questions/20884010/qt5-failed-to-load-psql-driver-in-windows</a><br>
<br>
"It's quite likely to be failing because there's a dependency of <code>qsqlpsql.dll</code>
missing - either <code>libpq.dll</code>, or one of the libraries
that <code>libpq</code> build requires." ... "<span
class="comment-copy">You should use the <i>same</i> libpq your
Qt's <code>qsqlpgsql.dll</code> was compiled against if possible.</span>"<br>
<br>
If that's true, how should I know with what <span
class="comment-copy">libpq library qsqlpgsql.dll was compiled in.
I suppose </span>PyQt 5.13.2's <span class="comment-copy">qsqlpgsql.dll
is compiled with different version than </span><span
class="comment-copy">PyQt 5.14.x's <span class="comment-copy">qsqlpgsql.dll
or even </span></span><span class="comment-copy"><span
class="comment-copy">5.15.x's <span class="comment-copy">qsqlpgsql.dll</span></span>.<br>
<br>
Also, this link has some clues:<br>
<a class="moz-txt-link-freetext" href="https://stackoverflow.com/questions/26507353/qpsql-driver-not-loaded-qt">https://stackoverflow.com/questions/26507353/qpsql-driver-not-loaded-qt</a><br>
<br>
And generally, what's the best way to work with </span><span
class="comment-copy">PostgreSQL in PyQt5. It obviously doesn't
work out of the box if </span><span class="comment-copy"></span><span
class="comment-copy">PostgreSQL is not installed on client
machine, and even if the wrong version is installed.<br>
<br>
</span>Nenad<br>
<br>
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