Connect to MySql 8.3?
lazarus / 16-Databases

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Kepsz · 2024-03-12 11:15

Hi,

Is there a way to connect MySql 8.3 database at this time?

The TMyesql80Connection component in Lazarus can only connect to 8.0
The ZeosDBO can only connect up to 5.7, it's the same with the current
trunk r8099 version too.


So far I managed to handle the Windows platfrom specific issues on
Win10 x64 to get the needed dll files, thanx to "Dependencies"
https://github.com/lucasg/Dependencies program to figure out the needs
of libmysql.dll:

-download the MySql .zip https://dev.mysql.com/downloads/shell/ to get
libmysql.dll file and put that next to the app .exe file.
-install Visual C++ Redistributable for Visual Studio 2015 x64
https://www.microsoft.com/en-us/download/details.aspx?id=48145
-download OpenSSL .zip
https://kb.firedaemon.com/support/solutions/articles/4000121705 to get
these files:
libcrypto-3-x64.dll
libssl-3-x64.dll
and put those next to the app .exe file.

But I see no way forward to connect to a MySql 8.3 database.

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rvk · 2024-03-12 11:20

Quote from: Kepsz on March 12, 2024, 12:15:34 pmIs there a way to
connect MySql 8.3 database at this time?
The TMyesql80Connection component in Lazarus can only connect to
8.0You can check SkipLibraryVersionCheck.

I'm still puzzled as to why there isn't just a generic
TMySQLConnection.
I can't imagine the version differences are that high, and if there
are, they can be handled by a version check of the library.
Now the developer always needs to make sure the correct library is
installed. Nuts?

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Zvoni · 2024-03-12 11:48

Probably because of this:
https://dev.mysql.com/doc/relnotes/mysql/8.3/en/news-8-3-0.html
Scroll down to Section "API"
QuoteThe following deprecated C API functions have been removed:

    mysql_kill(): Use mysql_real_query() or mysql_query() to execute a
KILL statement instead.
... more C-API's following
Just looked into the mysql.inc-File in
C:\lazarus\fpc\3.2.2\source\packages\mysql\src\mysql.inc

e.g. mysql_kill is still there

No idea about main/trunk

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rvk · 2024-03-12 11:52

Quote from: Zvoni on March 12, 2024, 12:48:06 pmProbably because of
this: https://dev.mysql.com/doc/relnotes/mysql/8.3/en/news-8-3-0.html
Scroll down to Section "API"
QuoteThe following deprecated C API functions have been removed:

    mysql_kill(): Use mysql_real_query() or mysql_query() to execute a
KILL statement instead.
... more C-API's following
Just looked into the mysql.inc-File in
C:\lazarus\fpc\3.2.2\source\packages\mysql\src\mysql.inc

e.g. mysql_kill is still there

No idea about main/trunk
Ok, So there are differences. But wouldn't it have been better that
those were handled by a generic TMySQLConnection.
It can query which library is used and act accordingly.

If a developer has several different client and servers, it would be a
pain to program them all in with different connections.
Using one TMySQLConnection would be so much more convenient.

I don't use MySQL so I don't really care, but for instance... Firebird
also has different libraries and they are handled in one IBX component
(I assume the same goes for TIBConnection).

But ok. I guess that's the reason the SkipLibraryVersionCheck was
created... a decade too late

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Zvoni · 2024-03-12 12:01

Quote from: rvk on March 12, 2024, 12:52:42 pmQuote from: Zvoni on
March 12, 2024, 12:48:06 pmProbably because of this:
https://dev.mysql.com/doc/relnotes/mysql/8.3/en/news-8-3-0.html
Scroll down to Section "API"
QuoteThe following deprecated C API functions have been removed:

    mysql_kill(): Use mysql_real_query() or mysql_query() to execute a
KILL statement instead.
... more C-API's following
Just looked into the mysql.inc-File in
C:\lazarus\fpc\3.2.2\source\packages\mysql\src\mysql.inc

e.g. mysql_kill is still there

No idea about main/trunk
Ok, So there are differences. But wouldn't it have been better that
those were handled by a generic TMySQLConnection.
It can query which library is used and act accordingly.

If a developer has several different client and servers, it would be a
pain to program them all in with different connections.
Using one TMySQLConnection would be so much more convenient.

I don't use MySQL so I don't really care, but for instance... Firebird
also has different libraries and they are handled in one IBX component
(I assume the same goes for TIBConnection).

But ok. I guess that's the reason the SkipLibraryVersionCheck was
created... a decade too late 

The funny thing is: There IS only one mysql.inc, though smattered with
a lots of {$IFDEF MySQLVersion} blabla
Yes, there are the "different" mysqlX.Xconn.pas files, but those are
(more or less) just placeholders, which import the inc-file with
setting the Defines beforehand

Funfact 2: Excerpt from mysql.inc
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 {$IFDEF
Unix}  {$DEFINE extdecl:=cdecl}  const    mysqllib =
'libmysqlclient.'+sharedsuffix;  {$IF DEFINED(mysql80)}    mysqlvlib =
mysqllib+'.21';  {$ELSEIF DEFINED(mysql57)}    mysqlvlib =
mysqllib+'.20';  {$ELSEIF DEFINED(mysql55) or DEFINED(mysql56)}   
mysqlvlib = mysqllib+'.18';  {$ELSEIF DEFINED(mysql51)}    mysqlvlib =
mysqllib+'.16';  {$ELSEIF DEFINED(mysql50)}    mysqlvlib =
mysqllib+'.15';  {$ELSEIF DEFINED(mysql41)}    mysqlvlib =
mysqllib+'.14';  {$ELSE}    mysqlvlib = mysqllib+'.12'; 
{$ENDIF}{$ENDIF}{$IFDEF Windows}  {$DEFINE extdecl:=stdcall}  const  
mysqllib = 'libmysql.dll';    mysqlvlib = 'libmysql.dll';{$ENDIF}
The API-declares all call on mysqllib (the one WITHOUT Version-Info on
Linux)
mysqlvlib (The one WITH Version-Info on Linux) is only needed when
trying to initialize MySQL
(Just did a CTRL+F in Geany)
QuoteFunction InitialiseMysql(argc: cint; argv: PPchar; groups:
PPchar) : Integer;

begin
  Result := 0;
  if (RefCount<>0) then
    // pretend to load whatever is already loaded, so we do not get a
library name conflict.
    Inc(RefCount)
  else
    If (TryInitialiseMysql(mysqllib,argc,argv,groups)=0)
       and (TryInitialiseMysql(mysqlvlib,argc,argv,groups)=0) then
      Raise
EInOutError.CreateFmt(SErrDefaultsFailed,[mysqlvlib,mysqllib]);
  Result := RefCount;
end;
That said: Just looked at some source-files of Mysql in the Dev-Zone
of their page: They don't offer an exported function to read out the
library-version?!?!?

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rvk · 2024-03-12 12:30

Quote from: Zvoni on March 12, 2024, 01:01:25 pmThe funny thing is:
There IS only one mysql.inc, though smattered with a lots of {$IFDEF
MySQLVersion} blabla
Yes, there are the "different" mysqlX.Xconn.pas files, but those are
(more or less) just placeholders, which import the inc-file with
setting the Defines beforehandYeah, if only those IFDEFs were done
like if/else depending on the loaded library, like with all other
connection components for other databases 

Quote from: Zvoni on March 12, 2024, 01:01:25 pmThat said: Just looked
at some source-files of Mysql in the Dev-Zone of their page: They
don't offer an exported function to read out the library-version?!?!?
Yikes? At least on Windows they have version information in the
properties. But you would really like a exported version for it to be
sure.

Doesn't mysql_get_client_info() or mysql_get_client_version() give the
client info?
https://dev.mysql.com/doc/c-api/8.0/en/c-api-function-reference.html

https://dev.mysql.com/doc/c-api/8.0/en/mysql-get-client-info.html
https://dev.mysql.com/doc/c-api/8.0/en/mysql-get-client-version.html

It's even used in function TConnectionName.GetConnectionInfo()

So, all those different TMySQLXXConnections could be rewritten to one
TMySQLConnection.
The older ones can stay a wrapper for backwards compatibility. They
would even work with newer clients in that case

No need to make newer ones because that can be done dynamically in the
new TMySQLConnection.

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Zvoni · 2024-03-12 12:55

Quote from: rvk on March 12, 2024, 01:30:02 pmYikes? At least on
Windows they have version information in the properties. But you would
really like a exported version for it to be sure.

Doesn't mysql_get_client_info() or mysql_get_client_version() give the
client info?
https://dev.mysql.com/doc/c-api/8.0/en/c-api-function-reference.html

https://dev.mysql.com/doc/c-api/8.0/en/mysql-get-client-info.html
https://dev.mysql.com/doc/c-api/8.0/en/mysql-get-client-version.html

It's even used in function TConnectionName.GetConnectionInfo()

So, all those different TMySQLXXConnections could be rewritten to one
TMySQLConnection.
The older ones can stay a wrapper for backwards compatibility. They
would even work with newer clients in that case

No need to make newer ones because that can be done dynamically in the
new TMySQLConnection.
You're right. Missed those.
And both are available in 8.3

Just looked again in mysql.inc - InitialiseMySQL
Both "Tries" must be satisfied (And condition).
Haven't looked too closely: is the libmysqlclient.so a symlink to
libmysqlclient.so.21 (or whatever suffix) or the other way round?
Because if the so is a symlink to the so.xx then the second try should
not be neccessary.
Just read out the client-version AND THEN set the Defines incl. the
second try?

If that's even possible.......
IIRC, defines are constants at compile-time, no?

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Kepsz · 2024-03-12 12:59

Quote from: rvk on March 12, 2024, 12:20:18 pmQuote from: Kepsz on
March 12, 2024, 12:15:34 pmIs there a way to connect MySql 8.3
database at this time?
The TMyesql80Connection component in Lazarus can only connect to
8.0You can check SkipLibraryVersionCheck.

Oh, I did not know about that property. Thank you!