Problems with MySQL

[Ingvar Engelbrecht]

I have working code for access to MySQL in MT5/MQL5. It uses the modules ANSI2UNICODE and UNICODE2ANSI

works file in MT5. tested with bad password and the translatd message comes out fine.

I have exactly the same code  in MT4/MQL 4.

Gives my errno  2003  and untranslatable errormessage  

?

[Stanislav Korotky]

I can assume that MT4 accepts ANSI strings while MT5 works with Unicode.

[Ingvar Engelbrecht]

I have seen a message that Build 600 of MT4 and higher does not support ANSI.

I started out with ANSI on MT4.

[Alain Verleyen]

ingvar_e:

I have seen a message that Build 600 of MT4 and higher does not support ANSI.

I started out with ANSI on MT4.

Yes MT4 uses now Unicode string.

How can we help ? Can you provide a snippet of code to demonstrate your issue ?

[Ingvar Engelbrecht]

angevoyageur:

Yes MT4 uses now Unicode string.

How can we help ? Can you provide a snippet of code to demonstrate your issue ?

[Ingvar Engelbrecht]

ingvar_e

Code in MQL4 EA and MQL5 EA

#ifdef __MQL5__
#import "MySQLFunc.ex5"
 bool SetParms(string host,string user, string pass,string signalsDB,string signalsTable,string parmsTable,uint port);
 bool connectToSQL();
 bool CreateParmsTable();
#import
#else
#import "MySQLFunc.ex4"
 bool SetParms(string host,string user, string pass,string signalsDB,string signalsTable,string parmsTable,uint port);
 bool connectToSQL();
 bool CreateParmsTable();
#import
#endif

Code in MQL4  and MQL5.  Resides in one ex4 library and one ex5 library:

bool connectToSQL() export
 {
  string moduleID = "[ConnectToSQL] ";

  
     MyDB2   = UNICODE2ANSI(MyDB);
     MyHost2 = UNICODE2ANSI(MyHost);
     MyUser2 = UNICODE2ANSI(MyUser);
     MyPass2 = UNICODE2ANSI(MyPass); 
/*
     MyDB2   = MyDB;               //if before build 600
     MyHost2 = MyHost;
     MyUser2 = MyUser;
     MyPass2 = MyPass;
 */

  
  mysql = mysql_init(mysql);                //This works ok in MT4 and MT5
  if(mysql == 0)
   {
    Print(moduleID+"Init mysql_init failed!");
    mysqlOK = false;
    return(false);
   }
   
   Print("Init mysql_init ok:  " + mysql);
   
  int res =  mysql_real_connect(mysql,MyHost2,MyUser2,MyPass2,MyDB2,MyPort,"",0);
    
    if(res != mysql)
     {
       Print(moduleID+" Connectfailed res :  " + res + "  mysql: " + mysql);
       Print("errno: " + mysql_errno(mysql));
       string ww = mysql_error(mysql);
       Print("error: " + ww);
       string ww2 = ANSI2UNICODE(ww);
       Print("Error translated : " + ww2);
       
       return false; 
     }

     
   return true;
 }
 

Results:

running MT5 with correct PW

Mysql_init OK

Print:    "Tables created"

Running in MT5 with bad PW

mysql_init ok

Print:  "Error 1045"

Print   A lot of japanese symbols

Print translated: Access denied for user

So MT5 behaves as expected

Running MT4 with correct PW

Print "error:  2003

Print Just a bunch of question marks and a couple of number 4 digits

Print translated:  nothing, blank

[Alain Verleyen]

ingvar_e:

It probably means there is something in UNICODE2ANSI that doesn't work with mql4.

Why not simply use StringToCharArray() ?

[Ingvar Engelbrecht]

angevoyageur:

It probably means there is something in UNICODE2ANSI that doesn't work with mql4.

Why not simply use StringToCharArray()?

Interesting thought. Will investigate. Thanks

Hmm. Nobody been using MT4 >600 with MySQL?

[Ingvar Engelbrecht]

Been looking around. Problem has been around for quite  a while. No good solutions found.

What would be nice is MQL4 source for ANSI2UNICODE and UNICODE2ANSI. I really do not like to use "wrappers" which seems to be the solution suggested

I am using a Library for my MySQL functions and I would like it o be common for MQL5 and MQL4 (Compiler directives accepted) and it has these functions in MQL5

[Alain Verleyen]

ingvar_e:

Can I suggest you to not answer inside the quote. It's very annoying. Thank you.

[Ingvar Engelbrecht]

Sorry about that

Found the solution. The originator of the ANSI2UNICODE and UNICODE2ANSI had made an update to the original code from 2010

http://mqlmagazine.com/mql-programming/dll-hell-mql5-edition-unicode-vs-ansi/

Look in comments!

Very simple to change with compiler directives so that the code works both in MQL4 and MQL5

Tested OK, Case closed