Unattended Install of SQL Server 2005 Express with LOCAL Server InstanceName - sql-server-2005

Question

I'm creating an install package using InnoSetup and installing SQL Server 2005 Express. Here's the code below that appears in my RUN section:
Filename: "{app}\SQL Server 2005 Express\SQLEXPR.exe" ; Parameters: "-q /norebootchk /qn reboot=ReallySuppress addlocal=all INSTANCENAME=(LOCAL) SCCCHECKLEVEL=IncompatibleComponents:1;MDAC25Version:0 ERRORREPORTING=2 SQLAUTOSTART=1 SAPWD=passwordhere SECURITYMODE=SQL"; WorkingDir: {app}\SQL Server 2005 Express; StatusMsg: Installing Microsoft SQL Server 2005 Express... Please Wait...;Check:SQLVerifyInstall
What I'm trying to accomplish is have the SQL Server package install but only have the instance name itself reference the name of the machine name and nothing more. What I'm receiving instead is a named instance instead of local such as MachineName\SQLEXPRESS which is not what I want to receive.
I need a local instance instead of a named instance due to the way my code is written to be able to install and talk with the databases in question. I would change it, trust me, were it not the fact that this install package is a replacement to a previous package that used the MSDE installer. I have to be able to support both through code. Any suggestions are welcome but a clear and concise method to get the installer to quietly install using only the machine name is my main goal. Thanks for the help and support!

Answer 1

Here's a sample for setting the InstanceName in code:
; Script generated by the Inno Setup Script Wizard.
; SEE THE DOCUMENTATION FOR DETAILS ON CREATING INNO SETUP SCRIPT FILES!
[setup]
; NOTE: The value of AppId uniquely identifies this application.
; Do not use the same AppId value in installers for other applications.
; (To generate a new GUID, click Tools | Generate GUID inside the IDE.)
AppId={{4D044938-6185-4729-8EB9-33CFA5D51993}
AppName=My Program
AppVerName=My Program 1.5
AppPublisher=My Company, Inc.
AppPublisherURL=http://www.example.com/
AppSupportURL=http://www.example.com/
AppUpdatesURL=http://www.example.com/
DefaultDirName={pf}\My Program
DefaultGroupName=My Program
OutputBaseFilename = setup
Compression = lzma
SolidCompression = yes
[Languages]
Name: "english"; MessagesFile: "compiler:Default.isl"
[Tasks]
Name: "desktopicon"; Description: "{cm:CreateDesktopIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked
[Files]
Source: "SQLEXPR.exe"; DestDir: "{app}"; Flags: ignoreversion
; NOTE: Don't use "Flags: ignoreversion" on any shared system files
[Run]
Filename: "{app}\SQLEXPR.exe" ; Parameters: "INSTANCENAME={code:MyInstanceName|'SQLEXPRESS'}";
[Code]
function MyInstanceName(Param: String): String;
begin
//This sets the value to \MSSQLSERVER.
Result := ExpandConstant('{computername}') + '\MSSQLSERVER';
end;
However, from what I've seen on the net the instance name should be MSSQLSERVER if you want it to be the default instance on the machine.