Zeos ZConnection problems with PostgreSQL
lazarus / 16-Databases

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JD · 2016-03-16 13:09

Hi there everyone,

I'm having a rather curious problem. I use Zeos 7.2 RC along with
Lazarus 1.6/FPC 3.0 Win32. I also have PostgreSQL 9.5.1 Win32
installed. I wanted to connect to a PostgreSQL database in the Lazarus
IDE using TZTable & TZQuery and browse the results in a DBGrid.

Anytime I try to set TZConnection's Connected property to True, I get
the error in the attached image below saying libpq.dll was found BUT
could not be loaded. Check compile target & library compatibility.

It can't be a 32bit/64bit issue because everything I use for
development is 32bit. In addition, the same test program works without
problems when I replace Zeos components with SQLdb components shipped
with Lazarus.

Thanks for your assistance with resolving this issue.

JD

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goodname · 2016-03-16 13:26

The libpq.dll actually depends on a number of other dll's. It is
possible that the other dll's are not being found.

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rvk · 2016-03-16 13:40

Or that the other found dll's are invalid.
Like a wrong version of ssleay32.dll in the Windows/System32 or
something.

I think libpq.dll is depended on (if this list is still current):
comerr32.dll
gssapi32.dll
k5sprt32.dll
krb5_32.dll
libeay32.dll
libiconv2.dll
libintl3.dll
msvcr80.dll
ssleay32.dll

https://pgolub.wordpress.com/2008/12/15/building-postgresql-client-
library-using-mingw-under-winxp-sp3/

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JD · 2016-03-16 14:03

I've actually posted the issue on Zeos' forum also because like I said
Lazarus' SQLDb components connect & show data without problems. I am
also able to administer PostgreSQL databases using both dBeaver and
pgAdmin. So I don't think it is a case of missing dlls.

I'm still looking into this curious issue.

JD

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rvk · 2016-03-16 14:48

You could try setting TZConnection's Connected property to True in
code and directly after it (after the error) read out GetLastError.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
ZConnection.Connected := true;Showmessage(IntToStr(GetLastError));
A failed LoadLibrary would leave it's errorcode behind in LastError.
Maybe it gives a more clear description (after searching the internet
for the numbercode )

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miab3 · 2016-03-17 12:05

I tried copy client libraries from PostgreSQL 9.5.1.1-32

zlib1.dll
libeay32.dll
libiconv-2.dll
libintl-8.dll
libpq.dll
libxml2.dll
libxslt.dll
ssleay32.dll

in the application directory (ZEOS 7.2.1-rc, LAZARUS 1.6-Win32)
and connect to the server (9.3) without problems.

I see that it is also used msvcr120.dll.

Michal

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JD · 2016-04-11 09:47

I only just saw this today. Thanks a lot for your replies. Following
miab3's advice, I copied the files to the project's main directory.

While I was able to connect successfully, I was unable to browse a
table in DBGrid using ZTable. When I click on any row in the grid or
try to scroll, I get the dreaded SIGSEGV exception! See attached.

I tried using ZQuery & then the project hung when I tried to set
ZQuery active i.e
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
ZQuery.Active := True.

The funny thing is everything works fine with SQLdb components even
without copying all these files around.

JD

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tsr · 2016-04-19 21:05

Share some simple test application with this issue please. I will look
at it.
Do you try it on different operating system?

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miab3 · 2016-04-20 23:38

@JD,

See what works for me
ZEOS 7.2 (7.3):
http://zeoslib.sourceforge.net/viewtopic.php?f=40&t=3795&p=61481#p6065
6

Michal