以下是借鉴网上诸多网友的代码经过整理和修改而来。
下面是示例代码，注意压缩数据库的代码同时可以用于修改密码。

unit DataProc;

interface

uses Windows, SysUtils, ADODB, Variants, ComObj;

const
  ConStr = 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=%s;'
         + 'Jet OLEDB:Database Password=%s';

function BuildConnectionString: String;
function CompactDatabase(DB: String; OldPass: String='';
  NewPass: String=''): Boolean;
function CreateAccess(pAccess: String; Pass: String=''): Boolean;
function RepairDatabase(pDBFile: String; Pass: String=''): Boolean;

implementation

function GetTmpFile: String;
var
  LPath: String;
  LFile: array[0..MAX_PATH] of Char;
begin
  LPath := ExtractFilePath(ParamStr(0));
  if (GetTempFileName(PChar(LPath), '~data', 0, LFile) <> 0) then
  begin
    DeleteFile(LFile);
    Result := LFile;
  end;
end;

function BuildConnectionString: String;
begin
  Result := PromptDataSource(0, '');
end;

function CompactDatabase(DB, OldPass, NewPass: String): Boolean;
var
  dao: OleVariant;
  TmpDB: String;
begin
  TmpDB := GetTmpFile;
  try
    dao := CreateOleObject('JRO.JetEngine');
    dao.CompactDatabase(Format(ConStr, [DB, OldPass]),
                        Format(ConStr, [DB, NewPass]));
    Result := CopyFile(PChar(TmpDB), PChar(DB), False);
    DeleteFile(TmpDB);
  except
    Result := False;
  end;
end;

function CreateAccess(pAccess: String; Pass: String=''): Boolean;
var
  cat: OleVariant;
begin
  try
    cat := CreateOleObject('ADOX.Catalog');
    cat.Create(Format(ConStr, [pAccess, Pass]));
    Result := True;
  except
    Result := False;
  end;
end;

function RepairDatabase(pDBFile: String; Pass: String=''): Boolean;
var
  dao: OleVariant;
begin
  try
    dao := CreateOleObject('JRO.JetEngine');
    dao.RepairDatabase(Format(ConStr, [pDBFile, Pass]));
    Result := True;
  except
    Result := False;
  end;
end;

end.