Why do I need a Delphi console to work with TSQLConnection?

Question

I have a simple console application written using Delphi XE2.

program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  Data.DBXMSSQL,
  Data.DB,
  Data.SqlExpr;

var
  myConnection: TSQLConnection;

begin
  try
    { TODO -oUser -cConsole Main : Insert code here }

    myConnection := TSQLConnection.Create(nil);
    myConnection.DriverName := 'MSSQL';
    myConnection.GetDriverFunc := 'getSQLDriverMSSQL';
    myConnection.LibraryName := 'dbxmss.dll';
    myConnection.VendorLib := 'sqlncli10.dll';
    myConnection.LoginPrompt := False;
    myConnection.Params.Clear;
    myConnection.Params.Add('drivername=MSSQL');
    myConnection.Params.Add('schemaoverride=%.dbo');
    myConnection.Params.Add('hostname=myserver');
    myConnection.Params.Add('database=mydb');
    myConnection.Params.Add('blobsize=1');
    myConnection.Params.Add('localcode=0000');
    myConnection.Params.Add('isolationlevel=ReadCommited');
    myConnection.Params.Add('os authentication=True');
    myConnection.Params.Add('prepare sql=False');
    myConnection.Connected := true;

    Writeln('myConnection Is connected');
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;

  Readln;
end.

When I run this, I get this error:

'DBX error: The driver cannot be correctly initialized. The client library may be missing, not installed properly, the wrong version, or the driver may be missing on the system path. ''

If I add a VCL form to the application, I get a pop-up window about including the "Visual Component Library" frame, which I say No , and without doing anything else, now when I launch the application, I get "myConnection Is connected".

The only difference I see is in the uses clause:

uses
  System.SysUtils,
  Data.DBXMSSQL,
  Data.DB,
  Data.SqlExpr,
  Unit1 in 'Unit1.pas' {Form1}

Unit1 'Unit1.pas' {Form1} uses, .

, , , ?

Answer 1

VCL CoInitialize ( COM ), ( , COM ).
CoInitialize CoUninitialize .

http://docwiki.embarcadero.com/RADStudio/XE5/en/DbExpress_Database_Specific_Information