求助

[ljhxuer]

在delphi7中我用sqlServer2000数据库，用SQLConnection1和数据库成功连接上了，SQLQueryLogin与SQLConnection1连接上了，现要做一个登陆界面，在“登陆”事件中有如下，代码：
procedure TForm1.SBnloginClick(Sender: TObject);
begin
//DataModule2.SQLQueryLogin.comm.CommandType:=ctQuery;
if RBnteacher.Checked=true then //½ÌʦÉí·ÝÑéÖ¤
begin
if Accounts.text<>'' then
begin
DataModule2.SQLQueryLogin.DataSource:=DataModule2.DataSource1;
DataModule2.SQLQueryLogin.SQL.Clear;
DataModule2.SQLQueryLogin.SQL.Add('select TeaId,TeaPwd from Tea_info.db');
DataModule2.SQLQueryLogin.SQL.Add('where TeaId=(:Teaid)');
DataModule2.SQLQueryLogin.Params[0].AsString:=Accounts.Text;
DataModule2.SQLQueryLogin.PrepareStatement;
DataModule2.SQLQueryLogin.Open;
if DataModule2.SQLQueryLogin.Fields[0].AsString<> null then
if DataModule2.SQLQueryLogin.Fields[1].AsString=Password.Text then
begin
Form1.Close;
FrmTea.ShowModal;
end
else
begin
ShowMessage('ÃÜÂë´íÎó');
Exit;
Password.SetFocus;
end
else
begin
ShowMessage('ÕʺŲ»´æÔÚ£¡');
Exit;
Accounts.SetFocus;
end;
end
else
begin
ShowMessage('ÕʺŲ»ÄÜΪ¿Õ£¡');
Exit;
end;
end
else
if RBnstudent.Checked=true then //ѧÉúÉí·ÝÑéÖ¤
begin
if Accounts.text<>'' then
begin
DataModule2.SQLQueryLogin.DataSource:=DataModule2.DataSource1;
DataModule2.SQLQueryLogin.SQL.Clear;
DataModule2.SQLQueryLogin.SQL.Add('select StuId,StuPwd from Stu_info.db');
DataModule2.SQLQueryLogin.SQL.Add('where StuId=(:Stuid)');
DataModule2.SQLQueryLogin.Params[0].AsString:=Accounts.Text;
DataModule2.SQLQueryLogin.PrepareStatement;
DataModule2.SQLQueryLogin.Open;
if DataModule2.SQLQueryLogin.Fields[0].AsString<> null then
if DataModule2.SQLQueryLogin.Fields[1].AsString=Password.Text then
begin
Form1.Close;
FrmStu1.ShowModal;
end
else
begin
ShowMessage('ÃÜÂë´íÎó');
Exit;
Password.SetFocus;
end
else
begin
ShowMessage('ÕʺŲ»´æÔÚ£¡');
Exit;
Accounts.SetFocus;
end;
end
else
begin
ShowMessage('ÕʺŲ»ÄÜΪ¿Õ£¡');
Exit;
end;
end;

end;

[hellolongbin]

问题呢？