How to check if an OLEDB driver is installed on the system?

Question

Hi! How can I make sure that a certain OLEDB driver is installed when I start my application? I use ADO from Delphi and would like to display a descriptive error message if the driver is missing. The error that's returned from ADO isn't always that user-friendly.

There are probably a nice little function that returns all installed drivers but I haven't found it.

Answer 1

Wouldn't the easiest way just be trying to make a connection at start-up and catching the error?

I mean you might get a few different errors back depending on, for example, the user is online, but they're cases that you should be able to test for.

Answer 2

I believe the OLEDB objects in question are buried someplace in the registry, since OLEDB / ADO is a COM solution. My guess would be to see if you can find the GUID that your driver is installed as in the registry.

Answer 3

skamradt is correct. Each provider has a GUID associated with its class. To find the guid, open regedit and search the registry for the provider name. For example, search for "Microsoft Jet 4.0 OLE DB Provider". When you find it, copy the key (the GUID value) and use that in a registry search in your application.

function OleDBExists : boolean;
var
  reg : TRegistry;
begin
  Result := false;

  // See if Advantage OLE DB Provider is on this PC
  reg := TRegistry.Create;
  try
    reg.RootKey := HKEY_LOCAL_MACHINE;
    Result := reg.OpenKeyReadOnly( '\SOFTWARE\Classes\CLSID\{C1637B2F-CA37-11D2-AE5C-00609791DC73}' );
  finally
    reg.Free;
  end;
end;

Answer 4

You can get a ADO provider name and check it in registry at path HKEY_CLASSES_ROOT\[Provider_Name].

Answer 5

namespace Common {
  public class CLSIDHelper {

  [DllImport("ole32.dll")]
  static extern int CLSIDFromProgID([MarshalAs(UnmanagedType.LPWStr)] string lpszProgID, out Guid pclsid);


  public static Guid RetrieveGUID(string Provider) {
    Guid CLSID = Guid.Empty;
    int Ok = CLSIDFromProgID(Provider, out CLSID);
    if (Ok == 0)
       return CLSID;
    return null;
  }
 }
}