CODEWITHSUNDEEP
mysqldelphiodbc
sav
sav

Reputation: 2150

MySQL connection prompts for password even though this is in the connection string

This one looks like a bizarre one.

I have a Pascal unit that connects to a MySQL database

unit u_MySQLConnection;

interface

uses
  ADODB,
  AnsiStrings,
  Generics.Collections,
  SysUtils,
  DB
  ;

type
  TMySQLConnection = class
    strict private
      mysqlCon : TADOConnection;
    public
      function Connect:boolean;
      destructor Destroy;
  end;

var
  MySQLConnection : TMySQLConnection;

implementation

function TMySQLConnection.Connect:boolean;
var
    success : boolean;
begin

    success := true;
    try

      if NOT (mysqlCon = nil)
      then mysqlCon.Destroy;

      mysqlCon := TADOConnection.Create(nil);

      mysqlCon.ConnectionString := 'DRIVER={MySQL ODBC 3.51 Driver}; SERVER=localhost; DATABASE=database; UID=root; PASSWORD=password;OPTION=3;';

    except
        success := false;
    end;

    Result := success;
end;

destructor TMySQLConnection.Destroy;
begin
    FreeAndNil(mysqlCon);
    inherited;
end;

end.

And when I try to connect

MySQLConnection := TMySQLConnection.Create;

try
    MySQLConnection.Connect;
finally
    MySQLConnection.Destroy;
end;

I get a password prompt dialog box appearing, even though the password is already in the connection string. If I enter the username and password into this prompt, everything else works fine.

Things get a little bit more strange here:

When i move the database connection command into the main .dpr file as shown

program DieselBatch;

uses
  Vcl.Forms,
  u_MySQLConnection in '..\src\u_MySQLConnection.pas'
  (*,
  frm_About in '..\src\frm_About.pas' {frmAbout},
  frm_AnalystDetails in '..\src\frm_AnalystDetails.pas' {frmAnalystDetails},
  frm_Batch in '..\src\frm_Batch.pas' {frmBatch},
  frm_ConfirmResultsChanged in '..\src\frm_ConfirmResultsChanged.pas' {frmConfirmResultsChanged},
  frm_DebugSample in '..\src\frm_DebugSample.pas' {frmDebugSample},
  frm_FlashManualEntry in '..\src\frm_FlashManualEntry.pas' {frmFlashEntry},
  frm_Main in '..\src\frm_Main.pas' {frmMain},
  frm_SampleComment in '..\src\frm_SampleComment.pas' {frmSampleComment},
  frm_SelectAnalystForResult in '..\src\frm_SelectAnalystForResult.pas' {frmSelectAnalystForResult},
  u_Data in '..\src\u_Data.pas',
  u_MicroCheck in '..\src\u_MicroCheck.pas',
  u_Undo in '..\src\u_Undo.pas'
  *)
  ;

{$R *.res}

var
  MySQLConnection : TMySQLConnection;

begin

  MySQLConnection := TMySQLConnection.Create;

  try
      MySQLConnection.Connect;
  finally
      MySQLConnection.Destroy;
  end;

Then the password prompt does not appear, as long as those units are commented out.

When I uncomment the above units again, the problem reappears.

Some of those units do use ADODB and DB but I can't see how the mere presence of the units should affect the behavour of the MySQLConnection unit ....

Upvotes: 3

Views: 1170

Answers (1)

jachguate
jachguate

Reputation: 17203

Short answer

Set the LoginPrompt property of the connection object to False.

Why it does not appear when you comment all the form units?

Well, the common DoConnect method of the TCustomConnection descendants checks the LoginPrompt property and then calls the LoginDialogProc/LoginDialogExProc procedural variable if assigned. The variables are declared in Data.DB.pas.

The VCL itself assigns this variables in the initialization section of the VCL.DBLogDlg.pas unit, which contains the standard dialog box you see, and this unit is used by the DBCtrls.pas unit, and automatically added to your project when you use any data-aware control.

If you comment out all the units containing data aware controls, the DBCtrls.pas unit is not linked in your executable and, as a consequence there's no registered login dialog to show when you're connecting.

Upvotes: 12

Related Questions