Check if psqlodbc has been unistalled or not from the system - delphi

Question

Im working on software that required psqlodbc drivers and postgresSQl 9.0 database,
we have a installer designed using delphi 7 to install both psqlodbc and postgreSQl 9 silently
one after the other on click of a single button, here everything runs fine,
but the problem is during uninstall,
i first want to unistall psqlodbc and then postgreSQl 9 also on a sinlge button click,
i want to run the postgreSQl 9 unistaller using shellpApi only after psqlodbc has been unstalled,
as of now im checking for 'cmd.exe' is running or not to start postgreSQl uninstaller, but sometimes after unstalling psqlodbc the 'cmd.exe' remain n the postgreSQl unistaller cannot be executed,
so any please tell me
how to check if psqlodbc uninstall process is completely.
the files are
1.psqlodbc.msi
2.postgresql-9.0.2-1-windows.exe
install/uninstall is handled wit bat file
thanks in advanced:)

Answer 1

You can check registry if driver is available. When it is installed you will get:
c:\tmp\pg>reg query "hklm\SOFTWARE\ODBC\ODBCINST.INI\PostgreSQL ANSI"
! REG.EXE VERSION 3.0
HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\PostgreSQL ANSI
APILevel REG_SZ 1
ConnectFunctions REG_SZ YYN
Driver REG_SZ C:\Program Files\psqlODBC\0900\bin\psqlodbc30a.dll
DriverODBCVer REG_SZ 03.00
FileUsage REG_SZ 0
Setup REG_SZ C:\Program Files\psqlODBC\0900\bin\psqlodbc30a.dll
SQLLevel REG_SZ 1
UsageCount REG_DWORD 0x1
And when you unistall it you will get (localized version):
c:\tmp\pg>reg query "hklm\SOFTWARE\ODBC\ODBCINST.INI\PostgreSQL ANSI"
Błąd: system nie może odnaleźć określonego klucza rejestru lub wartości.
c:\tmp\pg>
(this menas: Error: system cannot find key or value in registry)
See: reg /? on how to use it and for return code you can use in batch.
You can also search registry uninstall information under HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall

Answer 2

I got how to check if psqlodbc has been uninstalled completely so that i can start unistalling postgres
For that i found the solution
On stackoverflow itself
function TForm1.ExecAndWait(const CommandLine: string) : Boolean;
var
StartupInfo: Windows.TStartupInfo; // start-up info passed to process
ProcessInfo: Windows.TProcessInformation; // info about the process
ProcessExitCode: Windows.DWord; // process's exit code
begin
// Set default error result
Result := False;
// Initialise startup info structure to 0, and record length
FillChar(StartupInfo, SizeOf(StartupInfo), 0);
StartupInfo.cb := SizeOf(StartupInfo);
// Execute application commandline
if Windows.CreateProcess(nil, PChar(CommandLine),
nil, nil, False, 0, nil, nil,
StartupInfo, ProcessInfo) then
begin
try
// Now wait for application to complete
if Windows.WaitForSingleObject(ProcessInfo.hProcess, INFINITE)
= WAIT_OBJECT_0 then
// It's completed - get its exit code
if Windows.GetExitCodeProcess(ProcessInfo.hProcess,
ProcessExitCode) then
// Check exit code is zero => successful completion
if ProcessExitCode = 0 then
Result := True;
finally
// Tidy up
Windows.CloseHandle(ProcessInfo.hProcess);
Windows.CloseHandle(ProcessInfo.hThread);
end;
end;
end;
so step # 1
if ExecAndWait('msiexec /x C:\psqlodbc09\psqlodbc.msi') then
begin
//uninstall postgresNow...!!
end;