Connect to mysql from a console app hangs in IDE but not out of it
lazarus / 16-Databases

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kokorini · 2010-02-15 20:25

Hello. First: thanks for reading.


now, I'm trying to connect to mysql from a console application.

Using an application where you drag an drop controls to the form it
connects OK but I don't know why I can't make it work on a console
app.

here is my code, it loads from an external .txt the configuration,
that works fine:

Code: [Select]
      MySQL := TMySQL50Connection.Create(nil);
      MyTransaction := TSQLTransaction.Create(nil) ;
      MyQuery := TSQLQuery.Create(nil);

      MyTransaction.Database := MySQL ;
      MyQuery.DataBase := MySQL ;
      MyQuery.Transaction := MyTransaction ;
      MySQL.Transaction := MyTransaction ;

       AssignFile(F, config_file_name) ;
       reset(F) ;
       readln(F,mysql_host) ;
       readln(F,mysql_user) ;
       readln(F,mysql_pass) ;
       readln(F,mysql_dbname) ;
       closefile(F) ;

       MySQL.HostName := mysql_host ;
       MySQL.UserName := mysql_user ;
       MySQL.Password := mysql_pass ;
       MySQL.databasename := mysql_dbname ;

       MySQL.Connected := True ;


And... when the last line is excecuted the program stop responding, no
errors, no exceptions... just nothing.

OH! just after I post,  I have an idea: run the program without the
IDE... IT WoRKS!!!

so, the problem is that when I'm in the IDE, the program stop
responding when I try to connect. But I runs ok if I run it from a
console, without the IDE.

lazarus bug?? hope not

this is a TCustomApplication, with lazarus 9.28.2-0

thank you
FGrant

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fredycc · 2010-02-15 22:32

Hi kokorini I works with firebird & Zeos but is similar for establish
connection, I use similar code for threading app with firebird, maybe
the problems is your query because you have nothing; test it:

      MySQL := TMySQL50Connection.Create(nil);
     
      AssignFile(F, config_file_name) ;
      reset(F) ;
      readln(F,mysql_host) ;
      readln(F,mysql_user) ;
      readln(F,mysql_pass) ;
      readln(F,mysql_dbname) ;
      closefile(F) ;

      MySQL.HostName := mysql_host ;
      MySQL.UserName := mysql_user ;
      MySQL.Password := mysql_pass ;
      MySQL.databasename := mysql_dbname ;

      Try
   MySQL.Connected := True;
      except
   on E: Exception do
    Showmessage(E.message)
      end;

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kokorini · 2010-02-16 15:43

Hi... thank you for your help.
but it didn't solve the problem, when connect := true  the programs
hangs in the IDE and not out of it.

trying "things" I reduce the program to minimal like this:
Code: [Select]program Project1;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, mysql50conn, sqldb
  { you can add units after this };

{$IFDEF WINDOWS}{$R project1.rc}{$ENDIF}
var
 conn : TMySQL50Connection ;
 s : string ;
begin
  conn := TMySQL50Connection.Create(nil);
  conn.Connected := True;  //THE PROGRAM HANGS HERE
  s := 'nothing' ;
end.

I know I haven't set the host, username, nothing... but setting those
things before connect give the same result.
Let me be more clear...
if I put a breakpoint on the line when the comment "//the program...."
the program never pass that line. But if I excecute the program from
the console, it works fine (setting the hostname, username, etc... of
course).

I tried to see what happend without settings hostname, username, etc
to see if it was a version problem with the mysql server, but becouse
it hangs in the same way, I think the problem is on the IDE, or it
seems to be.

I'm using a very fresh ubuntu 8.04 32bits installation, with a fresh
lazarus.

thank you again
FGrant